you see i put archangel early for most mana bonus as soon as possible so as soon as possible max ap available out it. and not to get oom very quickly, also a soul shroud early in build so i can't die quickly. thne i get a will of the ancients, so my bomb, that will eventually blast a whole minion wave at once, heals me as well, and you'd be a better support with it because your lane mate will also advantage the 25% spell vamp of it. and at last you get zhonya's hourglass that if it happens you get main targeted you disable the target and you keep alive as a support.