does anybody know any reincarnation stories where the person being reincarnated is strong ...

A damn good novel on this: http://www.readlightnovel.com/true-star

What lies at the end is kind of a recarnation story...and he's got a very badass personality but it's more of a body swap story

Here are just a couple. Hope this is helpful. (⌒▽⌒)

http://www.mangago.zone/read-manga/kumo_desu_ga_nani_ka/

http://www.mangago.zone/read-manga/arifureta_shokugyou_de_sekai_saikyou/

http://www.mangago.zone/read-manga/tensei_shitara_slime_datta_ken/

http://www.mangago.zone/read-manga/fenglin_tianxia_wangfei_shisansui/

http://www.mangago.zone/read-manga/tales_of_demons_and_gods/

http://www.mangago.zone/read-manga/remonster/

http://www.mangago.zone/read-manga/hiraheishi_wa_kako_wo_yumemiru/

http://www.mangago.zone/read-manga/revival_man/

http://www.mangago.zone/read-manga/shut_hell/

Bokura no Kiseki,
Kurenai Ouji.

Uraboku