Does strength do anything else besides adding attack? if not then isnt the pet tiger the same as the pet dragon? cause if 1 str = 5 attack, then they both give out the same damamge.

tiger gives off more attack power but i can't remember the reason for it
just like the unicorn gives off more hp than the lion

Tiger adds str, str = dmg, if you have items on like say for example, a lightning card in your suit +3-7% dmg, the str getts the % boost. if you have a dragon + 100 attk, it isn't boosted by lighting cards/%dmg. it just adds the 100dmg at the top of your dmg. str is better.

but lion gives hp/def and depends on the class.. knights give a lot more hp per sta then others

and like easican said.. str gives exponencial dmg by % itens