If you took Momonga from Overlord and Rimuru into comparison, I’d say both their power and ethics is very similar. Massive amounts of power, rarely uses it but somehow doesn’t dissapoint, will do anything to defend allies.
The main protagonist of the series and Founder and King of the city known as Tempest. Originally Mikami Satoru, a 37-year-old salaryman, he was stabbed by a passing robber while protecting one of his co-workers and reincarnated in a new world as a slime, the lowest monster on the food chain.
In spite of the situations he finds himself in, he often tends to be very easygoing, yet calculating and cautious. A pacifist at heart, he tries to avoid casualties and save people if possible and wishes to maintain good relations with humans.
Rank: SS (True Demon Lord)
Title(s): King of Tempest, Demon Lord, Newbie (New Star/New Face), Great Demon Lord
Magic: Magic Power-Based Archive, High Spirit Summoning, High Demon Summoning, Dragon species magic
Species Skill: Disintegration Absorption, Infinite Regeneration.
Ultimate Skill: Wisdom King Raphael, Gluttonous King Beelzebub, Covenant King Uriel, Storm King Verudora, Puppeteer, Wisdom God Ciel, Void God Azatoth, Abundance king Shub-Niggurath.
Daily Skill: Magic Perception, Heat Detection, Sound Detection, Super Sense of Smell, Demon Lord’s Haki, Universal sense, Universal transformation.
Combat Skill: Sticky Steel Thread, Cloning, Chaos Breath, Law Manipulation, Attribute Change, Thought Domination, Demon Lord Mode/Transformation.
He later becomes an Awakened Demon Lord in an effort to save one of his subordinates from clutches of death with an offering of 10,000 human souls.
The onset of such a transformation is often beset by a change in personality, and as such following the event, he became more subtly malevolent with his intentions, his often pacifist nature became less dominant and he became more comfortable with killing or taking violent actions to protect the ones he cares about.