Glenn Lodbrok story is developed in Ever Crisis. He's a P0 SOLDIER, i.e. a prototype of SOLDIER who is not physiologically enhanced (no mako and no Jenova cells injections). So.
Ff7 Glenn
Glenn was a story character in that game. He's from the dead mobile FF7 battle royale spinoff game. Thats pretty much all I know about him. I've gone further in and his.