Subaru's description is barely a drop in a deep deep pond of suffering, explaining will take several paragraphs, and i will just summarize stuff that i remember offhand, probably will miss a lot. Btw don't read this if you are anime only and don't want to be spoiled.
Summouned to another world, saw it as a new start for him, dies over and over realizes his ability is return by death, returning to back to a specific point in time by dying, dies some more, eventually solves the issues in the capital, goes to mansion thinks he made friends with the maids there, turns out they want to kill him, dies some more, eventually solves the issues there.
But still thinks he is the protag in a ln, the world decides to prove him wrong, can't tell anyone about his power, so he can't explain his situation to anyone. Gets his ass whopped by julius for white knighing emilia, emilia leaves him cause he feels the obsessive need to always be with her.
Proceeds to watch the person he cares for die over and over, everyone forget her, and again can't even explain his situation in fact when he tries to, shadowy hand or should i say satella kills emilia, so not only is rem erased from his existence, trying to explain it to emilia gets her killed, then gets killed by giant beast thing, so he decides to run away but eventually decides to stay due to rem giving one of the best speeches in recent anime imo. Everything is looking up he has gathered around him, then gets killed by his best friend julius cause crazy cultist betelguese took over his body.
And after all the issues are resolved, existence erasing whale is dead, crazy cultist who killed rem is dead, turns out he couldn't save rem cause she has been erased from existence by another crazy cultist and nobody remembers her, also crusch also got screwed her arms chopped off and memory erased, subaru proceeds to kill himself multiple times to try to go back in time and save rem but he can't.
Summarizing arc 4 is too much of a pain, essentially he dies as usual over and over, including getting eaten alive by what he thought were cute rabbits, among other painful deaths, this dude literally felt them eating him alive but could do anything or die for a while, but lets ignore all that he finally meets someone who he can tell his suffering about but turns out even that as a consequence of telling his situation to someone else when he returns from meeting that person, satella is killing everyone he cares for and he has to kill himself or she would absorb him and then he couldn't return by death anymore.
And the person he could tell his suffering to? Well turns out she isn't interested in helping him but his ability and wants to experiment with it, having him die over and over just to see the result (he accepts her offer of help oin what if story by the author and that is brutal dude kills himself just to tell his friend what the weather will be later). This is a major thing in arc 4 whether he will mercilessly sacrifice himself or value himself. He also manage to convinced an insane guy who knows about his ability and was plotting to kill everyone to be his ally but if he lets anyone die, this guy will kill everyone he loves.
Also remember his ability to essential reset time? Turns out it might not do that simply take him to parallel worlds, so everyone he thought he saved by dying, might still be dead.
After arc 5 a lot of his friends are pretty messed up. His best friend has everyone forget about him, rem is still comatose, he is screwed up cause he was poisoned and had his leg messed up, a lot of people were turned into flies etc.
And it doesn't end there, arc 6 comes around he is trying to save rem who is comatose and nobody remembers so he goes to a tower, as usual dies over and over, being burned alive his head exploding etc. When he reaches the tower, he losses his memories and somebody is going around killing his comrades and turns out that person is natsuki subaru, so somehow he or somone else possessing his body is killing his love ones over and over, and he has no memory of who he is or how he even came to the tower.
