I enjoy being Chara. Like, A lot. Chara is everything i wish I was irl. One of the roleplay's I frequent has somebody who roleplays the integrity soul. And they have single handedly caused chara to get banned in-universe. Even the word integrity makes me sick to my stomach now. Thanks for listening.
Wubboc doesn't have a soul, he uses souls as a power source, this power source, of course, runs out.
That's why wubboc eateds so much, so he can maintain high energy levels.
Spinel Seraphim Undertale has the SOUL of DETERMINATION. For a Gem monster who has existed for 6,000 years and also had been cursed by Chara which lead to the extinction of MILLIONS of timelines, she burns sickly with DETERMINATION and WRATH.