I got Flat AP quints, AP per level glyphs, and soon getting Magic Penetration Marks.
But for the seals I'm using some extra Magic Resist seals I got, but should I change the seals? I tried Mana regen per level, and they were useless.
What do you think?

try seals with flat mana regen(not per level) and buy flat ap glyphs i think its more useful imho

hp/lvl if u go vs magic damage champ, armor if vs physical damage

Why?
They are almost equal at lvl6, and on lvl7+ mp5/lvl are much better. It's not like CDR glyphs.
On the other hand LeBlanc is an exceptions because she benefits a lot from flat mana regen seals cuz she can kill other champs at lvl2.


For AP rune page i suggest MP5/lvl if u have only normal "mana" mages.
If u like to play katarina or ryze then hp/lvl are better (cuz they are not behind like other mages and they need that HP, also with Ryze u go for max Mana so you really dont need mana regen).

Mp5 per lvl are better end game but end game u should have some items like RoA Archangel and so on and you wont have mana problems end/mid game(except for few champs like anivia who spam ult)
with those rune i can spam Q with karthus withour go oom, i go oom only if i abuse of my e early game.
obv if u spam spells early lvl u will always go oom

those are also a choice but i use them only if i play with champs without mana like mordekaiser
Seal armor, glyph mresist, marks mpen/flat hp/ap Quints hp/ap it depends but im not a great morde player so i may be wrong