Then I believe you are re talking about this one:
http://www.mangago.zone/read-manga/ore_to_kawazu_san_no_isekai_hourouki/
You also have the one when MC purposely give them horrible nickname that they all hate:
http://www.mangago.zone/read-manga/tensei_kyuuketsukisan_wa_ohirune_ga_shitai/
Are you talking about this one?
http://www.mangago.zone/read-manga/the_rhapsody_of_me_and_her/
I don’t remember it well if he/she did tend to mess with people name though XD
And this is why protagonists should never be allowed to name things/beings.