This duo boss guards the way to the Divine Tower of East Altus, which is accessed by making your way through Leyndell, Royal Capital. The bosses are essentially two regular enemies from the Subterranean Shunning Grounds, slightly beefed up, but that doesn’t make them any less deadly. Fortunately, you don’t actually have to fight them both at once! In this guide, we’ll go over an easy way to split up — and defeat — the Fell Twins.
Strategy
You’ll have to walk forward (towards the corpse of the soldier) in order to get the Fell Twins to spawn. Once they do, immediately start sprinting away from them, and don’t stop running until you’ve ran for at least ~20 seconds. The right-hand twin will chase you, while the other just walks towards you, so running away like this means you’ll get to fight two 1v1s instead of a 1v2.
Once you’ve done your running away, you can summon a spirit — the 
Skeletal Militaman are probably the best choice, since they can survive the whole fight, and will get 1-shot by the twin’s attacks (which is actually a good thing, since we want to keep moving). Throughout the fight with the first twin, continue to move away from where the twins spawned — ranged characters can just run/roll backwards, while melee characters will need to aggro and pull the boss every so often.
Generally, you can bait out a combo and then run/roll out of range, but sometimes the bosses will do a grab attack (they’ll spread their arms wide and run towards you) — you have to let them finish this attack or they’ll chase you forever, so turn into them and roll once you’re very close.
Melee
Equip a 100% physical defense shield and fight defensively. Hold block and roll backwards to dodge attacks until the twin you’re fighting turns to face the skeletons you summoned (who should be poking him in the butt). Once the boss turns around, you can easily backstab him. (Don’t forget to regen stamina by letting go of block when you’ve got some space between you and the boss).
The twin’s attacks do a lot of damage, so you probably won’t be able to hold block the whole time — try to roll backwards whenever possible. If you have a heavy enough weapon, you can also stagger the twin you’re fighting with leaping heavy attacks rather than waiting for a backstab. Keep an eye on the way you came from — if you see the other twin approaching, aggro the boss (attack it until it turns towards you) and run away. Keep pulling the boss until you can no longer see the other twin.
Ranged
You should already be sprinting away from the first twin you’re fighting, and it will probably be chasing you. Get it to start a combo by turning around and sprinting towards it, then quickly turning around and running away — once it begins its attack, you can get out of range and then start attacking (you don’t have to wait until it finishes its combo).
Your summons will also pull aggro frequently, offering you even more opportunities to attack. Once the first one goes down, repeat this tactic on the second one!
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