In general special characters tend to be broken - they are either very cheap for what they bring and dominate games, or they are overpriced. I am fairly sure all our special characters are overpriced, though Chakaz is pretty decent even though he is expensive as well. If the characters really appeal to you, and you like the idea of buying or converting the model, then use them occasionally. Don't wheel them out every time though because you will probably get sick of them being such a big focal point of the army.
Well, not really, since the deliverance of itza (or how the spell is called) is his only spell and a direct damage spell according the erreta, so you can't channel it through the skinks I think Tetto'eko is the best. a few points for a loremaster with IF re-rollable comets and a deployment bonus. I think it is cool to use him with a heavens slann to make that 2 IF comets =D
Also with Kroak, if you roll irrisistable force, his spell just fails to go off. Yes, he does not mis cast, but that will keep him from being effective. Not to mention the one spell. I also think that Tetto'eko is the best one. Mazdamundi is ok, he is just soooooo expensive. Of them all, I have tried: Tetto'eko about 4-5 times. Well worth it most times. Mazdamundi about 2 times. Ok for what you pay. Chakax once. He died way faster than I would have thought. Tiq'tac' to 1 time. Did not come on the board until like turn 4 and did nothing to help the game. If I try him again, I will start him on the board. Oxytyl 1 time. He is really fun to play. I took him in order to take pot shots at a Teclis HE unit. He earned his points in Psychological warfare. The HE player was kind of freaking out about the sniper. It was fun. Oxy never scored more than one wound on teclis, but it was awsome to see the reaction in the other player. Tehehuin about 4-5 times. This special character is the second best in my opinion. He brings something unique to the army. Lore of Beasts. If you really want to use the transformation of Khadon spell, this is how you do it. Take a Beasts slann with plaque of protection. Roll the spells for the slann first. The slann cannot have Khadon. That leave Khadon for Tehehuin. I never got off the spell with him the one time that I tried this though.
I'm planning to take Tetto'eko to a tournament next spring. I was thinking of going way overboard and taking him, a heavens/loremaster Slann, and a level 2 priest with Plaque of Tepok to go for the triple IF comet. Very one-trick-pony but I'd love to see my opponent's reaction.
why use a heavens slann when u could just use another skink priest? One of the main reasons for a slann is so u can access another lore
Sadly our generic characters, when properly equipped, smash our SC's into the dirt. It's a function of an older army book, weird design decisions, an edition overhaul (including a new generic armoury of magical gear which make ours look like rusting junk for the most part) etc. Maybe the next time they update Lizardmen, we'll get useful abilities and properly-costed characters.