So there's quite a collection of tough optional bosses to tackle after finishing the main story. The berserker trials are probably your biggest challenge with 10 gravestones scattered across different realms, and once you've beaten them all you'll face king hrólf kraki who's absolutely brutal with his attack patterns. If you're up for something different, the valkyrie queen gná waits in muspelheim, and trust me she's incredibly fast with some really nasty combo moves that'll keep you on your toes.

Something interesting - there are these troll statues hidden around midgard, vanaheim and svartalfheim that you can wake up using the mystical heirloom. Each one's got their own fighting style, and blódugr steinn is particularly tough. You might also run into some flame and frost phantoms lurking in hidden areas, they love to ambush you with these huge area attacks that can catch you off guard if you're not careful.

There are also these mini-bosses scattered around like dreki, soul eaters and ancients that really test your combat skills. The cool thing is beating these challenges gets you some pretty sweet gear like the hilt of skofnung and flawless berserker armor, plus some rare materials you might want for upgrades. Just be ready for multiple attack phases and some pretty intense combat patterns, especially in those later fights where the environment itself can be just as dangerous as the boss.