As the title asks, what do you want or look for in a relatable character? Is it the age, personality, morals, struggle, where they came from, or how they see the world? Does the setting make them more relatable? Do you even want a relatable character? What makes them relatable in the first place?
The bare minimum : decent IQ for MC
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For complete list of traits to be "relatable" for me :
-smart
-good person
-but chaotic good (any methods are good for the goal)
-simply want a peaceful life
-cautious (bc they are smart and knows that the law of murphy makes that troubles will appear no matter what/in short, always prepared)
-want a partner but also not driven by sexdrive
-do things unexpected by most people
-very revengeful
-love justice/punish bad guys
-naive but forced to put walls around their fragile heart bc outside world is a goddamn hell
Basically :
The greatest estate developer
Or its my top2 favorite novel : History strongest husband (NU)
that is basically a 99% identical clone to estate-manhwa. Especially the MC that is near a clone to him, that he act like a clown but in fact got a wounded kind naive heart, but forced to do ruthlessless things for peaceful life.
So identical that its saddening to see estate get so much popularity despite HSH being near as good or in fact FAR better than it.
Also nukes. MC nuked armies. Yep heard me right, he nuked whole armies to oblivion. Also let me tell a secret, is that any(most) CN with MC using nukes are good.
(and harem that is as good as Mushoku Tensei's = useful harem = without them, MC would have failed)