Lost Sinner

The Lost Sinner is a boss in Dark Souls II.

Location
The Lost Sinner is located in Sinner's Rise.

Description
A possesed corpse or hollow slightly larger than the player, wearing an iron mask and a straightjacket. She wields a greatsword, and uses it with great speed and power.

Summoning
Lucatiel of Mirrah can be summoned for this battle.

Strategy
This is a challenging boss, and her difficulty is only made worse by the fact that the room she is fought in is normally very dark. This obscures her movements and prevents the player from locking on to her unless at close range. However, the room can be lit up. Defeating the Belfrey Gargoyles and getting the Bastille Key allows you to unlock the two doors on each side of the boss's fog door, and light the oil inside with a torch which illuminates the boss's room.

Even with the room lit, being careful is essential. Use your best shield and be ready to block her attacks, as she can easily stunlock you and kill you easily. Still, her attacks do high stamina damage when blocked, so be careful. Staying close and circling her, then attacking when she does her thrusting attack, is a decent tactic, but the boss jumps around the arena often so it may be difficult to stay consistently near.

Be careful when healing or using items as she is highly agressive and will not stop attacking for very long. She can be parried, but quickly jumps away before any sort of follow-up attack can be performed. Using magic against her is a very bad idea.

Attacks
Horizontal Slash Combo: Her most common attack, often done twice in a row. It can be blocked, but she often will follow this move up with a downward sword slam that will almost always break your guard if you don't dodge.

Thrusting Attack: A powerful stabbing attack with the greatsword. Stay close and circle around her. If she misses, it gives a good chance for the player to counterattack.

Vertical Slice: An upward slice, sometimes followed by a downward slice. Dodging is the best option.

Jumping Attack: Jumps out of view and attempts to hit the player with a falling attack.