Books One, Two, and Three of the Realm of Ethnya series.
Being pulled into another world to be a hero? That's for young men. Full of hopes and dreams, and clear set standards of right or wrong, empowered by their youth. They can rise up, and become shining beacons within those realms, full of righteous pride and steadfast in their morals. Banners of hope, to fight against the evils in front of them, with unwavering faith and fortitude.
You don't take old men.
Old men have seen the world through increasingly jaded vision. Lines of morality, blurred or non-existent, through years of hard, ambiguity. Right and wrong become non-existent, only a continuing path forward becoming the basis for their actions. The only defining code, the purpose for that next step forward.
It's a dangerous game to place your hopes in an old man…
-------------
So he finds himself waking up in another world. Not knowing if it is a dream, a delusion, or he died and was reincarnated in another universe, he does what he has always done. Put one foot in front of the other, and make a path for himself. A second chance. With whatever or whoever it takes, and by whatever means he can grab hold of...