Watashi no Kokoro wa Ojisan de Aru

A New Life As A Dark Elf!
Haruka Yamagishi, a 43-year-old, lonely salaryman without friends, family, or love. Never very good at expressing himself, he’s avoided building relationships with people and finds himself a withered old man before his time. Then one day, he wakes up in another world, only to discover he’s a dark elf, and a beautiful woman at that! Despite having a body as tough as steel and a vast reserve of magical power, the timid Haruka still goes through life indecisively. Yet she (he) forms a party with fellow adventurers twice her (his) age and steadily adapts to this new world. The middle-aged man who once gave up on bonding with others opens his heart and strives to grow as his new self in another world. So the curtain rises on a twisted but classic story of adventure!

[From Cross Infinite World]