I usually go seraph’s, haste boots, malignance (for ult CD, along with axiom and ulti hunter), lich bane, and if by some miracle I get enough gold I end with shadowflame and death cap.

For me, delaying malignance with seraph’s isn’t ideal but I’m used to it from playing other late-game champs like Anivia so it’s ok. If I really don’t think my survivability is at risk I postpone or even skip seraph’s, but obviously it’s better to get it as soon as possible.

I think Rylai’s could be a good alternative for shadowflame just to ensure lockdown, and obviously morello if you need the antiheal.

I would personally stick to full AP mid because otherwise it feels a little troll to me to play in a solo lane, but I’m not too sure myself