It was the Kardas set, but yeah, it's basically three amazing sets from what may be my favourite year of bionicle with regards to the large sets (not a fan of the small sets from that year - my favourite lines were probably the Bohrok and Rahkshi, even with them being mostly identical, there's something special about them for me, presumably nostalgia, and on the Toa side of things I adored the Hordika - Vakama Hordika was the first thing I ever ordered online - I think my mother had to sign up to ebay/paypal for it, because it wasn't in stores here. A lot of nostalgia there. That said if I had to choose a year I thought was the best, it'd probably be 07, the Barraki and Toa Mahri were really neat, all of them with nicely varied designs (some very interesting/unusual stuff on the former) while still looking cohesive.)
Axonn is my favourite of them - loved that set the moment I saw it, I just love the design and elements of it have featured heavily in a bunch of my MOC's - the white one standing next to the actual Axonn set there is basically a clone of the design with a bunch of modifications to make it look lankier/less squat, using the Axe as a shield (I think it's configured a little differently to the Kardas set), and a kinda "freeze gun" for a weapon - I built it as a dark hunter but the design and how much I liked how it came out changed the silly little backstory I had for it. The Axonn that is there has been partswapped to remove the red (replaced with black), add additional armor, and the tip of his axe was changed to the weapon from the Black Rahkshi as I really like that piece and after the color change it seemed to fit better. The one in the centre of it all (which has changed a little, though the main thing is just to a sword instead of the staff) uses that lovely hand design, alongside a bunch of other parts I always wanted to use in an MOC (Boss Roborider "Block" pieces and original Toa Torsos for limbs - upper arms/legs respectively, and Bohrok torsos for feet), though the design has changed slightly I think since then (some minor part changes and now it has a sword instead, one I build and really liked but found a bit long for most of the smaller models that looked nice with this one).
Ended up merging Brutaka and Fenrakk together into one model after I removed the Axonn from it to build the white guy I mentioned (which started out as a white axonn to compliment the black one because I had a lot of spare white pieces), along with some of the extra red parts I had left over (and later some I bought off bricklink or which came in some of the sets I bought more recently). It looks a bit goofy with the head coming off the shoulder like that but it was something I did years ago and with a little tinkering I ended up really liking the thing, and I think it adds a more uh "fused against their will" vibe to the model than "chained to a giant spider" does anyhow.
Anyway, those being my favourite sets and characters, you can probably guess how I feel about where the story stopped being updated, and it didn't help that I really disliked the snap-together design of most of the Hero factory stuff that was around when I got back into Bionicle (though I did like some of the heads and some of the earlier ones had those nice reinforced socket joints - very useful for larger MOCs), and I'm someone who preferred most of the later, more action-figure-y bionicle designs (the later small sets were too simple, but they were small sets). But then perhaps that only makes it worse - I can see that it was a step along the path to Hero Factory.
If I get around to getting them out again, I'll try to get pictures of some of my favourite ones - I do have a couple out still, but they need a bit of dusting etc and I'm kinda busy with Beyblade stuff right now.
(Surprise! Beyblade isn't the only thing I can ramble on endlessly about )