I can stand toe to toe with an adamantoise without using death. I actually never used death on them, because had my fill of the failures on Gigantaur and Neochu that I didn't want to do it endlessly with the adamantoise that I'd have to fight repeatedly anyway and not just once. There are several workable strategies and everything in the game is beatable with death, but it will require you to do a lot of work before you can be successful. If you want an early lead or whatever, Death is the cheap way out though it won't feel like it after you have failed 50 battles.