Black Wizard: Arise, My Undead Army!

(Rating just released, will rise later)

[Black Wizard + Genius + Undead Side + Ruthless Killing + Plane War + Slow Burn]

Lin En, terminally ill, did not understand why he had been thrown into this cruel other world.

Mother Earth generously granted him recording and analysis abilities (a small cheat isn't really cheating).

However, faced with a catastrophic start-stranded in a gang and about to be sold into "Nightingale House"-Lin En decisively chose "if you can't beat them, join them"!

From then on, the "Blood Hand Gang" gained a notorious "Abacus Snake".

He originally thought he could rely on the convenience brought by the gang to accumulate startup funds, but unexpectedly, a sudden turn of events disrupted his plan.

What? Wizards? Taking apprentices?

That's great! So I can become a noble mage too?

What the hell? A black wizard?