Echoes of the Lost Elf - Chapter 7 - : Changes over time

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates

“What’s my class?”[Beast Tamer – Class E]“..Seriously?”Lee Min-Jae was a workaholic with no social life who died slumped over his keyboard. When he opened his eyes, he was in an RPG-like world — but with the worst class imaginable: Tamer.Tamers were seen as useless. Weak. Limited to disloyal, expensive-to-keep wild monsters.But he wasn’t just any fool. He was a systems-obsessed gamer, an expert at finding exploits and shortcuts.With his cold, analytical mind, he chose to break the game’s rules — by leveraging the most reviled mechanic of all: contracts.Where others saw abomination, he saw an exploit. And he was ready to turn the worst class into something unbeatable.---------------This story have:[Adventure][Smut][MSmut] (no NTR).[Harem][System / LitRPG][Strategy] - cold planning, exploiting mechanics, creative use of abilities.[Cold and Calculating Protagonist] – no naive romance.[Worldbuildin] – rules, politics, economy.[No NTR] – the protagonist is not betrayed, no passive humiliation content.

I became the childhood friend of the protagonist in a novel. The childhood friend who died from taking drugs.

[When you cast a spell 1000 times, the damage of all skills will be permanently increased by +10000. At this time, your fireball spell is equivalent to TNT. 】

[You cast spells 300,000 times, permanently increasing the skill damage to +3 million. At this time, your fireball technique is equivalent to an atomic bomb explosion. 】

[You cast spells 80 million times, permanently increasing your skill damage by +800 million. At this time, your fireball technique is equivalent to a supernova explosion! 】

A global catastrophe is coming,

Lu Cheng returned from the apocalypse and returned to the first day of the disaster to unlock super god-level talents!

Endless Drain: Each time you cast a spell, the damage of all skills will be permanently increased by 10 points!

So, Lu Cheng silently stacked the layers and became invincible before he knew it.

The national war has begun and is besieged by the enemy’s coalition forces? It doesn’t exist. Do you understand the fireball deterrent?

A world-class BOSS with hundreds of millions of health points? I was hit by a fireball, what can I do?

God-level civilization invades and easily blows up the sun? My fireball technique is like the sun!

Until the gods joined forces to blockade and trapped Lu Cheng in the Forbidden Fire God Realm.

Lu Chengcai showed off the other 100 skills: “Who told you that I only know the fireball technique?”

- Description from novelbuddy