Chaos Blade

The Chaos Blade is a Katana in Dark Souls.

Availability
The Chaos Blade is forged from the Soul of Quelaag and a Katana such as an Iaito or an Uchigatana that has been upgraded to +10.

Characteristics
The Chaos Blade drains 20 HP from the player with each successful hit, making it one of the only weapons that can kill its wielder. It does, however, deal very high damage per second, and scales well with dexterity. Its moveset is very similar to the Uchigatana moveset from Demon's Souls, so it may appeal to Demon's Souls veterans.

As with other Chaos weapons, the Chaos Blade scales with Humanity. It also scales well with Dexterity, although not as well as a fully upgraded Uchigatana or Iaito. However the humanity scaling usually more than makes up for this.

The Chaos Blade has the potential for the highest physical damage of the Katanas, with easily the highest Physical damage per second with 10 humanity and 40 dexterity at around 450 damage per hit. Although it does not deal other types of damage and may do less nominal combined damage than, e.g, a Lightning Uchigatana, this is offset by the fact that the Chaos Blade does not have to bypass multiple defensive stats per hit. In practice, the Chaos Blade is the best eastern sword option for players who don't mind the feedback damage and do not have access to weapon enchantments.

Like the other Katanas, the Chaos Blade causes Bleed. The Chaos Blade causes more Bleed build up than other Katanas (36 compared to the default 33 of other Katanas).

Strategies
Against weaker enemies, using the Ring of the Evil Eye can help negate the damage caused by the Chaos Blade. Wearing Sanctus and/or using the Replenishment miracle will also help offset the feedback damage caused by the Chaos Blade.

Upgrades
The Chaos Blade is upgraded using 5000 souls and Demon Titanite.

Trivia

 * The Chaos Blade is similar to the Hiltless (a.k.a. Gripless) from Demons Souls', which also drained users' HP upon damaging its foe and had an uchigatana-like moveset.
 * The unique two-handed R2 attack for the Chaos Blade is identical to the two-handed R2 for the Uchigatana from Demons' Souls.
 * The Chaos Blade was going to be part of a side storyline involving Shiva of the East. This however was not present in the final game.
 * The Chaos Blade has the prefix "Chaos", but however does not deal fire damage like the weapon upgrade "Chaos". However, like other Chaos weapons, it does scale with humanity.