Ekans can be found in the following areas in SoulSilver: Routes 3, 4, 32, 33, and the Safari Zone. In HeartGold, it can only be found in the Goldenrod Game Corner or in the Safari Zone. In SoulSilver, Arbok can be found on Routes 3, 4, 26, and 27, as well as in the Safari Zone. In HeartGold, it can only be found in the Safari Zone.
Though generally underrated, Arbok does have many viable uses. Despite its subpar stats, it can be properly honed into a decent wall, thanks to its nicely balanced defensive stats and the possibility of it having Intimidate. With the right strategy and a decent moveset, it can have the potential to sweep, though it doesn't necessarily pack too much power. Glare, though it has generally low accuracy, can be a good support move.
Proton (Slowpoke Well): Since Ekans can't be poisoned, it actually does pretty well in this battle. Zubat can't hurt it at all, and Koffing can't really do anything either, since its strongest attack is Tackle. Ekans should be fine here, especially if it has Intimidate.
Gym #2 - Bugsy (Azalea Town, Bug-type): Defeat the Metapod and Kakuna with swift Bite attacks, and do not attempt parahax with Glare; they both pack Shed Skin. However, the Scyther is fast and can hit hard if you aren't careful; try using Glare on it to cripple its speed, then switch your Ekans/Arbok in for a more viable counter. However, remember that it has Quick Attack, so it still has the potential to hit first.
Rival (Azalea Town): Ekans can effectively shut down Gastly with its Bite. It can take on Zubat as long as it doesn't get confused by Supersonic, but it might have trouble with Quilava or Croconaw. Bayleef shouldn't pose too much of a threat, though. If you have an Intimidate Ekans, then you might want to switch it in on Croconaw to nerf its physical attacks.
Gym #3 - Whitney (Goldenrod City, Normal-type): Clefairy's Metronome is something to be wary of. Be very careful when handling it, try to use Glare for parahax then Bite it into oblivion. Cute Charm is also annoying, but the Clefairy shouldn't be too much of a problem. Arbok can actually be useful against Miltank if it has Intimidate: switch it in to get off that Attack drop, and if you have Dig on your Arbok, go for that if it tries to set up a Rollout chain. However, since Miltank is holding a Lum Berry, Glare-hax won't work against it unless you use it twice; even then, paralysis normally isn't worth two turns.
Rival (Burned Tower): Gastly and Zubat still suck, so you can kill them with Crunch. Intimidate Arbok is actually very good against whichever starter your rival may have. If you have Dig on Arbok, then you should be able to beat Magnemite.
Gym #4 - Morty (Ecruteak City, Ghost-type): Be careful of Hypnosis and Dream Eater if you do not pack Shed Skin. Demolish the Haunter and Gastly with Crunch (you should definitely have an Arbok with Crunch by this point in the game), but try not to use this Pokemon against Gengar; its high Speed and Special Attack can quickly make mincemeat of Ekans/Arbok. Arbok should be able to 2HKO Gengar with Crunch (OHKO if you're lucky), but beware of its powerful Shadow Ball and annoying Hypnosis.
Eusine (Cianwood City): You should be able to kill Drowzee with Crunch before it does anything, and even if not, you can take a hit from it. Haunter isn't even a problem. Electrode does pack Thunder, but Arbok's bulk should be good enough to take one and respond; you may need to either heal or switch, however, as even Arbok's attacking power is not that high.
Gym #5 - Chuck (Cianwood City, Fighting-type): Arbok's only use in here is nerfing Chuck's Pokémon's attacks with Intimidate. It does a decent job of tanking Fighting-type attacks thanks to its resistance, but if Arbok doesn't have Intimidate, then you probably shouldn't use it here.
Gym #6 - Jasmine (Olivine City, Steel-type): If you pack a Ground-type attack, use it on the Magnemite; Dig will be enough for the OHKO. Do not bother with the Steelix; its impressive bulk will let it shrug off most attacks made by Arbok, and poison won't do anything for you here. Make sure you have adequate backup to destroy the Steelix, and you'll be fine.
Petrel (Team Rocket HQ): Crunch everything that isn't a Koffing. That thing can explode, so stay away from it unless you're desperate. While Intimidate makes it very unlikely to OHKO you, a critical hit will ignore that.
Ariana (Team Rocket HQ, tag battle with Lance): Since Arbok should be higher levelled than Ariana's at this point, there should be no big issues in this battle. Take Drowzee down fast so it can't confuse you, then focus on Ariana's side of the battlefield. Murkrow is the peskiest enemy here, with a combination of Wing Attack and Pursuit, so be careful of who you have out when it enters the battlefield.
Gym #7 - Pryce (Mahogany Town, Ice-type): Arbok doesn't necessarily do well nor badly here. It probably won't be able to hurt anything unless it has either Sludge Bomb or Iron Tail; use Sludge Bomb on the Seel and Dewgong, and Iron Tail on the Piloswine, since it lacks Earthquake. Its Mud Bomb might hurt, though.
Petrel (Goldenrod Radio Tower): Everything can explode and hurt a brickload. Do NOT tread. Use a proper physical tank for this.
Rival (Goldenrod Underground): Golbat can be troublesome with Confuse Ray, but unless it gets a crit on Air Cutter, it shouldn't be able to really do much to Arbok. Haunter can be swiftly dispatched with Crunch, but it might be able to do some damage before it goes down with its strong STAB Shadow Ball. Magnemite can be handled by Dig, but if your Arbok don't have any Ground-type moves, then you'll have some trouble. Sneasel might be tough, and it has a rather powerful Faint Attack as well as priority in Quick Attack. Intimidate Arbok may be able to switch in on Feraligatr to cut its attack, but Arbok won't be able to do much to either Feraligatr or Quilava (Meganium, on the other hand, can be slaughtered by a couple Sludge Bombs).
Proton (Goldenrod Radio Tower): Interestingly, his Weezing is the only one that can't explode. This makes it a lot easier to deal with, but it will still be slow to die since it has a high Defense. Golbat is mostly just annoying, but Arbok can make short work of it with Crunch or Iron Tail.
Ariana (Goldenrod Radio Tower): Not much has changed since the previous battle. It starts with an annoying Intimidate nerf on the other end, but you should be able to negate it by switching out, and then potentially back in. Arbok has no problem dealing with Vileplume, but might once again struggle to take a hit from Murkrow, so consider this carefully and determine whether or not to have something else fight Murkrow, depending on Arbok's health at that point.
Archer (Goldenrod Radio Tower): Houndour goes down easily to a single Dig. Koffing has Levitate and good physical Defense, so Arbok shouldn't even really try to take it down. It also poses a threat with SelfDestruct. Houndoom is dangerous and almost definitely won't go down to a single Dig (unless you're severely overleveled), so you should probably not use Arbok against it.
Gym #8 - Clair (Blackthorn City, Dragon-type): Arbok is neither good nor bad here. It doesn't take the strong attacks very well due to its decidedly average defenses and it can't do too much damage, either, but it can have some use in this battle as either an Intimidate user if it has Intimidate or a status absorber if it has Shed Skin.
Kimono Girls (Ecruteak Dance Theater): Arbok isn't good against any of the Kimono Girls. It gets wrecked by Espeon, it can't really touch Umbreon or Vaporeon, and Jolteon and Flareon are just plain too powerful for it to handle, even if you have Dig on your Arbok. You probably shouldn't use Arbok at all here.
Ho-Oh (Bell Tower, HeartGold only): Arbok can't be of much help here. Ho-Oh's Sacred Fire attack is way more powerful than it can handle, and Rock Slide isn't available yet. Don't use it here.
Lugia (Whirl Islands, SoulSilver only): There should be no need to explain why sending in a Poison-type against a Psychic-type legendary with a STAB move is a terrible idea.
Rival (Victory Road): Like before, Golbat and Haunter are both classed as "annoying, but not really dangerous". Don't do anything reckless against them, and you should easily win. Magneton can still be dispatched by Dig. Sneasel's offensive is more powerful than it's worth, so probably don't try that unless out of options. Kadabra needs to be avoided, and Feraligatr too unless Arbok can Intimidate it, or has previously set up Stockpile on another Pokémon. Even then, critical hits will hurt. Typhlosion is similar. Meganium is always easy instead.
Elite Four Will (Indigo Plateau, Psychic-type): It's very risky to use Arbok here. Even if you have Crunch on your Arbok, you still shouldn't use it here, since it will be facing off against STAB super-effective Psychics from powerful special attackers. Plus, Arbok isn't powerful enough for its non-STAB Crunch to be able to OHKO any of Will's Pokémon anyway.
Elite Four Koga (Indigo Plateau, Poison-type): Arbok can work decently here as a status absorber, especially if it has Shed Skin. It's immune to being poisoned, and Toxic, Koga's favorite strategy, will therefore not work on it. Beware of Double Team Crobat and Explosion Forretress, though; those things are full of hax and lethal because of it.
Elite Four Bruno (Indigo Plateau, Fighting-type): This battle is similar to the Chuck battle. If your Arbok has Intimidate, then feel free to use it here; if it doesn't, then it probably won't be able to do anything in this battle. Whichever ability it has, though, make sure to keep it away from both Onixes.
Elite Four Karen (Indigo Plateau, Dark-type): Another matchup that's neither good nor bad for Arbok. Sludge Bomb can work on the Umbreon, and if you poison it, then its Synchronize ability won't even work on you, since Poison-types like Arbok are immune to being poisoned. Arbok works well to kill Karen's Vileplume, but try to stay away from the powerful Houndoom and Gengar. Murkrow is kind of a middle-ground; it's frail but also pretty powerful, so if you're the cautious type, just use something with a little bit more bulk than Arbok against it.
Champion Lance (Indigo Plateau, Flying-type): Not worth it. Unless you have Ice Fang, Arbok can't really do anything in this battle besides soften his Dragonites' attacks.
From this point onwards, you can fight the gyms in any order, though you will need to retrieve the Machine Parts from the Cerulean City gym before you have access to the earlier portion of Kanto. Feel free to anticipate or postpone any battles as needed.
Gym #9 - Brock (Pewter City, Rock-type): Arbok can technically learn Giga Drain and completely wreck this gym. However, the TM is non-recoverable, and you probably want to save it for a Pokémon that needs it more. Keep Arbok out of this battle.
Rival (Mt. Moon, optional): Like Victory Road, but slightly different. Gengar is best not fought now that it can take a Crunch, and will likely move first and deal a lot of damage. Golbat is still doable. Sneasel should be, but like before, better not. Alakazam is more dangerous than ever and you shouldn't even think of approaching it. Feraligatr and Typhlosion are fine with prior setups, but not otherwise. Meganium and Magneton still go down easily with the right moves.
Gym #10 - Misty (Cerulean City, Water-type): Big NOPE to Golduck and Quagsire; the former has Psychic, the latter has Earthquake. Again, Giga Drain can work, but only for Quagsire (as Golduck will live a hit) and it's not worth it. Just finish off the rest with Poison Jab, which you should have gotten from Janine (go pick it up if you haven't). Starmie has Confuse Ray, which may be annoying, but no Psychic STAB.
Gym #11 - Lt. Surge (Vermilion City, Electric-type): Earthquake is a big winner against this gym. However, against the two Electrode, you should be careful. Do your calculations and make sure that Arbok can outspeed them, or they could explode in its face, which is never fun and might actually off Arbok in one go, if you aren't higher levelled enough. Alternatively, go Choice Scarf.
Gym #12 - Erika (Celadon City, Grass-type): Poison STAB is your friend. Grab Poison Jab and destroy everything. Even Victreebel, which technically isn't weak to it, can barely touch you.
Gym #13 - Janine (Fuchsia City, Poison-type): A tricky gym. Arbok is at a disadvantage against Crobat, but should win if it either has Rock Slide or a level advantage. Weezing has Explosion, so avoid it. You can remove both of the Ariados from the battlefield with your strongest non-Poison move, but switch out or heal if one of them uses Swagger on you. Venomoth has Psychic, so once again, nope.
Gym #14 - Sabrina (Saffron City, Psychic-type): It would take someone either insane or suicidal to use Arbok here. If you want it to live, don't even think about it.
Gym #15 - Blaine (Seafoam Islands, Fire-type): Everything here packs a really strong move, Overheat. Arbok can, however, outspeed Magcargo and kill it with Dig or Earthquake. As for Magmar, its base Speed is higher, though in a limited amount of cases - Arbok with a Speed-boosting nature and/or many Speed EVs, and/or higher levelled by at least four or five levels - you will actually outspeed it, and also OHKO. Alternatively, you can use a Choice Scarf to ensure this. Don't try it against Rapidash, however: it might live an Earthquake and kill you.
Gym #16 - Blue (Viridian City): Poison Jab makes short work of Exeggutor, and can work reasonably well against Pidgeot, in absence of Rock Slide. Arcanine, Gyarados, Rhydon and Machamp all either have Ground moves or a STAB that's too strong for Arbok to handle.
Rival (Indigo Plateau, optional): It's a repeat of the most recent battles all over again. However, since Crobat now has the upper hand over Arbok, it is best for the snake to not take part in the fight at all, unless it's to take down the usual Meganium and Magneton. The lack of good, non-threatening opponents makes it much harder for Arbok to set up Stockpile and hammer the rest.
Red (Mt. Silver): This fight is no joke. Arbok can outspeed Pikachu with a good EV investment and/or a Speed-boosting nature, and KO it with Earthquake. However, make sure to outspeed before you attempt this, or equip the Choice Scarf. Lapras should not be fought due to Psychic, and it is imperative to also avoid Snorlax, which has Giga Impact; Intimidate snakes may have it easier, but crits can always happen. The three starters are a toss-up; Charizard is the most dangerous, and may deal severe damage with Blast Burn, so either Rock Slide with the Choice Scarf handy (this assumes you switched out after defeating Pikachu, otherwise you will still be locked into Earthquake) or avoid it; Blastoise has Hydro Cannon, though it's not as strong as Charizard's Blast Burn. Still, be careful and have healing items handy. Lastly, Venusaur is fairly easy as Arbok resists all of its moves, though it's bulky and will take a while to go down.
Ekans starts off with Wrap and Leer, which is rather unimpressive, but the ability to deal some passive damage on top of poison is nice. Poison Sting, at level 4, is really only useful for the chance to poison. Bite, at level 9, provides some much needed power, and Glare at level 12 is handy for slowing things like Falkner's hax Pidgeotto down, although the shaky 75% accuracy hurts a bit. Screech, learned at level 17, can replace Leer, but Acid, at level 20, should just be skipped, as Bite has the same base power after STAB, while using Ekans' superior Attack stat. Upon evolving into Arbok at level 22, it will try to learn Crunch, which should immediately replace Bite. Level 28 brings the intended combo moves of Spit Up, Swallow, and Stockpile. While the first two are garbage, Stockpile's defense boosts can be paired with the TM for Rest, which means that, with Shed Skin, it has a 30% chance of having the sleep healed immediately, and the odds of having to sleep the standard rest time is a mere 49%. The only other level up moves worth consideration are the elemental Fangs (handy for dealing with pesky Steel types/Gyarados/Dragons), learned by Heart Scale, and Gunk Shot, which is an incredibly powerful STAB move, but its accuracy is a pitiful 70%.
Arbok learns a surprisingly large number of TMs and HMs, but only the ones it can use effectively will be listed. Poison Jab provides a more reliable STAB attack, if you're willing to wait until Kanto. Rock Slide and Rock Tomb are both excellent moves, but they are nonrenewable, and other Pokémon will likely want them more. Earthquake does not have this problem, surprisingly, if you're willing to spam the Battle Factory after the Elite 4, and Dig can provide an earlier alternative. Finally, the previously mentioned Rest can be paired with Sleep Talk for a bulky set, which actually works quite well with Arbok's solid defensive typing.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
Ekans Line Ratings
What Nature do I want? Adamant, Brave, Naughty, and Lonely are all quite good. Modest may also seem nice, as it will raise the power of Giga Drain and Sludge Bomb, but keep in mind that it’ll lower the power of your physical moves, such as Crunch, Dig, or Earthquake, which you will probably be using more often. Attack-lowering Natures are just plain bad, since Arbok’s Attack isn’t anything notable in the first place. A Defense-raising Nature along with Intimidate could prove handy in making Arbok a physical wall as well.
Which Ability do I want? Intimidate is the most useful, as it provides an effective boost in Arbok's not great Defense. Shed Skin may have the upper hand in select situations, but Intimidate will come in handy more often.
At what point in the game should I be evolved? Before Whitney, ideally. You should definitely have evolved into an Arbok by the time you reach Ecruteak City.
How good is the Ekans line in a Nuzlocke? Decent. It’s definitely nothing special, but Intimidate has the potential to be extremely useful when used correctly, and Arbok’s myriad of coverage moves allows it to take on almost any type of opponent. Its biggest drawback is that it has relatively bad stats, but it’s fun to use and is a true jack-of-all-trades, being able to act as a wall, a staller, an annoyer, or even a sweeper.
Weaknesses: Psychic, Ground
Resistances: Grass, Fighting, Poison, Bug
Neutralities: Normal, Rock, Dark, Steel, Ghost, Dragon, Fire, Flying, Ice, Water, Electric