Sacred 3

Unmissable, story related.

Defeat the Black Seraphim in the final mission of Underworld Story. This battle favors the use of the vampire weapon spirit, because one of the Black Seraphim's attacks takes nearly all your health away, leaving you with a dangerously low amount of HP. There's nothing you can do against it other than how you react afterwards i.e get healed soon. A few hits with the vampire weapon spirit will refill your health fast enough. You can also use the Orc character with his life leech weapon. After the attack, a few health orbs will spawn to help your healing process.

The 2nd attack of the Black Seraphim has bladed tentacles coming out of the ground. If you stay clear of these traps you're good to go. You can see the area they spawn just before they appear. Quickly move between the circles. If you get hit then it's an instant death, no matter the difficulty setting.

Also try to avoid the missiles the Seraphim shoots at you. These might take a large amount of health away. Especially after the health drain attack, it's critical not to get hit by these missiles.

Because of the scaling level, even on Warrior this fight will take a few minutes. If you pay attention to the tentacles, the only thing you need to do is get healed after the unavoidable spell that eats 95% or more of your health.