Talk:Kassadin/@comment-4948122-20120409224730/@comment-88.186.19.90-20120410174020

Masteries are usually 21/0/9, so get it. If you are building a little tanky you might want to go 21/9/0; either way it doesn't matter that much, since in either case what you gain doesn't give him a particularly important edge on his laning phase.

All mastery combinations are probably possible if you combine them properly: I saw Xpeke build him 9/21/0 with tanky runes against an Akali and I actually like to build him with 9/0/21, to immediately max CDR and drown my opponent in spells.

Red should always be magic penetration (magic, not armor). Mana regen, MR are also a must-have in my opinion, though depending on what items you plan to build and wether you get W at level 2 or 3, those mana regen slots can be used for something else. Armor, flat AP and per-level AP, CDR, Magpen are all good.