Kit: A friend introduced us to the anime, "The Time I was Reincarnated as a Slime". We'd been avoiding that one, because we thought it was going to be too silly (as opposed to, say, 'I was Reincarnated as a Spider, so What?'. We're really glad that we were able to watch them both. (We've been through the first season on both, and we're deep into the manga for the Spider one -- we might need to grab the manga for the slime one, not sure yet).
Spoilers Below. Lots of Spoilers.
So here's the thing. We've noticed that anime strongly follows the Shinto philosophy on a lot of points, and these two anime do so even more than normal. It's the kind of storytelling we enjoy, actually. Go figure.
There's some key take-aways from Slime.
In Shinto, natural forces are not considered evil - they act in accordance to their nature without malice. Outside factors may cause them to 'misbehave' - essentially an imbalance. A person is, for the most part, essentially good, but is not naturally balanced, so can cause imbalance / tragedy / conflict. Taking a life is a tragedy - an unclean act and one of the gravest sins of Shinto, but Shinto isn't about good vs evil, or punishing sin - it is about trying to find your own balance and harmony.
Also - what is in the past is in the past. You learn from it, but you don't let it control you. When dealing with others, you interact with them as if meeting them for the first time, and greet them as you would a neutral party until you discern how they are going to act now. This doesn't mean ignoring past actions - you can be as wary as you wish to be - but you don't bring up negative things from the past unless you plan to attempt to resolve them then and there.
So. Let's look at Slime.
The main character abhors taking life unless absolutely necessary - typically when in the defence of others, not itself. There is the rare example, but these are things that are a significant, dire threat, unintelligent, or will not relent. The slime tries to restrain enemies and offer them an opportunity to surrender or leave if possible.
Most enemies are enemies because of outside stresses or misunderstandings.
The restrained dragon? Befriended and a pact made.
The goblins? Befriended and watched after.
The dire wolves trying to kill the goblins? The hostile leader would not relent, and died. The rest? Spared and made allies.
The dwarves? Aided (even when imprisoned!) and allied.
The ogres? They lost their entire tribe and thought the slime was a maijin. Allied.
The obnoxious lizardfolk? Sent away, alive. Allied later.
The orc horde who devoured everyone and anything in their path? The leader had been effectively 'possessed', and manipulated by the said maijin. The slime ate him, discovered his tragic past of trying to save his tribe during famine, and gave him peace (sent him effectively to heaven). Then took the sins of the entire tribe even after they'd killed thousands (while cursed), put their past actions in the past, and gave them a home and a life. Consider them a 'natural phenomenon' that was driven to anger by outside forces. Once that was dealt with? It was considered in the past - who the orcs are now is what is important.
It is this attitude that allowed the slime to befriend a chaotic demon lord. He was able to get to the core of why she was who she was, and they became 'besties'. She's so chaotic because she is bored.
The scummy human that caused such problems in the dwarven city? He was only trying to be worthy of the king - and had lost his way due to envy. He was, in fact, not a bad guy, just a desperate guy. His past actions were set aside and he was given a home and work and befriended.
When a catboi gets possessed by a horrific demon? He's rescued, the demon slain, and he gets healed and returned to his master. His master's impressed with the slime's show of mercy and understanding, and they become allies.
The ifrit possessing someone he cares for, that's tearing down the town the slime's built? Captured and absorbed. Given a chance to become a better person.