Giant Lord

The best way to deal with this boss is by fighting it up close. That way, you don't have to worry about its massive sword. You just need to look out for its stomp and sword swings. Keep moving around, preferably behind it and anticipate the direction of its next attack.

There's a corpse sitting by the wall containing an Old Radiant Lifegem and another one after the stairs containing a Fire Seed. Go inside the doorway and examine a giant's corpse to get an item. You'll be instantly transported outside the memory after staying inside for a few minutes.