red relic
When I was first trying to get True Endning I decided to ask Reddit what the development way to get essence was, it was mostly just people noting that I missed Markoth and the Dream Bosses but someone accidentally said Soul Warrior instead of Soul Master. I was somewhat exited bc Soul Warrior didn't really feel like a boss and it was wondering what they had for him (at this point I had already encountered Failed Champion), and was disappointed when I realized he didn't have a dream boss.
The bosses name would be Soul Scholar and you would find him by Dream Nailing his chair in Sanctum, he would summon Folly's like his Elegant Key Room counterpart but he also summons Mistakes and maybe Soul Twisters (late into the fight), he would still look the same as base Soul Warrior and the arena would be Soul Sanctum when the infection had just hit and they started gathering SOUL, he would also steal SOUL from the player in order to use stronger spells (however he is very vulnerable while stealing) and once defeated his spirit would explain the horrors of the Sactum and how he slowly forgot who he was. While there are multiple Soul Warriors this would be the only one with a Dream Boss
wintry robin