Warrior is the starting class in Rogue Adventure. It's supposed to be basic and not overpowered so you can learn how to play the game with additional power and complexity introduced gradually. Naturally, increasing enemy HP and attack damage makes the starting deck increasingly inappropriate. Warrior has no starting ability that can scale with the difficulty level, so you will be relying on the cards and skills you find along the way in order to survive. World 1 can be the most difficult part of the run, because you need to ramp up quickly to defeat Gorilla King or Evil Forest Guardian. You will lose some runs early simply because you didn't find any good cards. Don't feel too bad about it.
This guide is here to help you beat Inferno 1 through 7 with Warrior in order to unlock the third Class Bonus, which makes temporary Strength and Resistance buffs become permanent buffs. When you equip Class Bonus 3, Inferno 8 should actually be easie