Anyone know of any isekai/reincarnation/whatever where the mc master mage/swordsman/doctor/scientist/cultivator/whatevers skills actually are completely useless in their new world/life. Say like if the dead level infinity master wizard is reborn in a sci-fi world without magic/mana so he or she has to start over from scratch creating robots or something... I don't mind if they still end up completely op, as long as they don't get it served on a silver plate and has to put in some effort for it.

Actually, feel free to recommend any isekai/rebirth story where the mc actually has to work for their op-ness.

~4400 manga completed
~1700 ongoing...

Hm... some that come to mind:

Arifureta Shokugyou de Sekai Saikyou is kinda like that, where the MC has to go through a gauntlet before he becomes OP, but that's only for the first volume (in the LN). But this is the more famous of the ones that have this type of story. It gets fairly generic and cliche as you read, but it fits the bill.

Technically Honzuki no Gekokujou isn't particularly useless at the beginning, and it's not your typical isekai with skills and cheats, but she is fairly weak and has to build what she wants from the ground up. Highly recommended.

If you don't mind older anime/LN, I'd also highly recommend Juuni Kokki (Novel). Youko never truly reaches peak OP-ness, but the story itself is gold and she does have to work through her own set of issues. It's a true fantasy series.

Another isekai/rebirth LN series I highly recommend is Saihate no Paladin (Novel). The MC has to go through a training (beginnings) arc that details his rise. It's heavily inspired by DnD, so if you're into that scene, you might also like this series.

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