Lone Wolf, I found fascinating and loved to play - but the balance was all over the place. The first book has lots of different paths to success, and not too many choices that you'd need for later. It's fun to pick up the Crystal Star Pendant, because that crops up a few times later on
as a recognition tool for bumping into Banedon but isn't vital.
Fire on the Water does have a one-true-path section, which can fuck you up if you don't have the magic item to defeat the particular undead threat. Gaining the Sommerswerd makes you nigh-on invincible in nearly every fight you get into after that point, but then the balance bafflers get muddled in Book 6 and you have to cheat the RNG gods to win.
I enjoyed book 3 (The Caverns of Kalte), and it offers up a couple of important special items - even if it opens with a multiple-Mungo scenario.
Don't miss out on the +2CS Silver Helm and the Kalte Firesphere that works as a perma-torch.Book 4 (The Chasm of Doom) introduces the idea of you being in charge of a larger force, then drops you into the middle of a major battle, and #5 (Shadow on the Sand) takes all your toys away
(but you can find them again if you look in the right place) and has you face off in combat against a major foe
(Darklord Haaken).
At that point you've become a Magnakai, and if you're having fun can continue your adventure with super-versions of the Kai Disciplines to collect - and you start with only three of them! You get to visit more distant lands, win a cool magic bow, lose all your stuff again in the Deathtrap Dungeon-like book #7 and get involved in a sort of continent-wide resurgence of the Drakkarim.
After defeating the ultimate evil in the final book (12), you find that (as a Grand Master) there are even more super-powered skills to learn in books 13-20. Amusingly, the things you have to fight in the opening section of Book #13 will eat you up and spit out your bones without breaking sweat - especially if you happen to still be carrying the Sommerswerd. So, y'know, ultimate evils are all about perspective. But Time Bandits taught us that.
And on it goes...