Good Grief! I Use Forbidden Spells Like Basic Attacks. That's Perfectly Reasonable, Right?

Lin Jin transmigrated to a world overrun by demons. On the day he changed classes, he awakened a one-in-ten-thousand class: the SSS-rank Forbidden Spellcaster!

What? Forbidden Spellcasters have long chants? Sorry, my forbidden spells don't need casting time.

What? Forbidden Spellcasters use too much mana? Sorry, my forbidden spells cost no mana.

What? Forbidden Spellcasters burn their lifespan when they use skills? Sorry, casting forbidden spells increases my lifespan!

Where are the promised Fireballs, Water Jets, Wind Blades, and Earth Clods? Why are they all world-ending forbidden spells?

While everyone else is still grinding the first floor of the Abyss with little Fireballs, he raises a hand and casts [Forbidden Spell: Falling Starflame], vaporizing the demons in an instant.

While everyone else thinks mages are weak in the early game, he casually conjures a [Forbidden Spell: Roaring Azure Thunder] that's just a tiny bit too powerful, leveling the exam grounds.

The principal saw the exam grounds blasted flat and spent the whole night revising the Forbidden Spell Control Regulations: no forbidden spells may be cast anywhere on campus.

When Lin Jin blasted through the Abyss with 999 forbidden spells, the entire Abyss collapsed into the shape of his magic.

“Good grief! Are you throwing forbidden spells around like normal attacks?”

“Other Forbidden Spellcasters risk their lives to cast spells, but you use them to stay healthy?”

“Fine, fine, casting forbidden spells even increases your lifespan. The King of Hell's ledger can't fit all your years.”