So what are some long running games with the same protagonist or that at least share a lot of characters?

Preferably a story rich one.

Like Rance series, and maybe Metal Gear.

Edit: Uncharted kind of fits too. Witcher is not exactly long, but you can put lots of hours into them.

There are good cutscenes and bad cutscenes.

It just happens most of them are bad.

Rance 10, a turn based game, is goddamn well balanced. Changing little things can make you win a battle you kept losing.

Monster Hunter is the best boss based game I know.

Other than that, I guess pretty much any game with some bullet hell mechanics, like Furi or touhou.

happens

Motion based: Furi

Turn based: Rance 10

Rance 10

Grisaia

KEY Visual novels

Portal 2

Persona 4/5

Killing Floor 2

Left 4 Dead 2

Monster Hunter World

Tekken + Guilty Gear + Blazblue + under night latest

and I used to really like CSGO

Furi

cuz time

Valve