The Poleaxe is such a cool weapon, I couldn't have Willas not using it. It's a fucking pike, with an axe attached. Like a lighter Halberd, almost. As demonstrated, while he might not use a sword, when you have full plate, two handed weapons become far more ballsy. He's most definitely not the best fighter, but he can hold people, for a long time indeed, and he really doesn't have a qualm with killing people. Not a psychopath, no, but he's weathered, far, far more than Garland (who I can imagine whilst having courage, and definitely being able to fight, wouldn't last long against someone who is skilled at the Water Dance).