1: who discovered this build first?
IIRC, Build First theorized by Ms. Refia. First build crafted was Mandelbrot. Midlumer and I developed the second craft.
2: what is the reason you made this build? To make eternal league more competitive? Or to give brain tumor to lower rank players?
The first reason for the craft came as the direct result of a challenge one year ago that the arena was a joke and No one made challenging PvP builds. There were other factors but this was primary. You could call playing these builds a Rite of Passage.
3: as a immortal build user if you face another immortal build how do you manage to beat it?
Patience and when I played, I only used the immortal craft to fight other players.
4:does immortal build primarily suited for wizard? Or can warrior and rogue reach the benefits of it same as wizard?
There are numerous ways to achieve quasi immortal build with any class, only one way has been deployed in arena.
5:did you get a sadistic joy when players cried about how op it is?
No - I thought many times to remove it from arena. I stopped playing PvP ~7 months ago. I did test a few items in that timeframe but nothing significant.
6:if dungeon quest 2 come will you make this build in there too? Or wait for some time to let the people enjoy different inferrior fun Builds even at the peak ?
Uncertain at the moment.
7:can immortal build be modified? Like mr cuzegspiked^s seasonal maiden build? if not do you really enjoy playing with same stufff over and over again?
Absolutely it can be made much more powerful and higher damage reduction. 
It was a very fun build for me to play.
8:when you fight in the arena do you often drag your character to near of your opponent and watch them for a few rounds how they cant put a scratch on you? I would do it if i could.
When I played, I would go direct!y to each challenger and attack face to face.
9:If this build reduces over%90 dmg in pvp does it makes you %100 resistant in pve?
One of my crafts had 100% Damage Reduction in PvE.
10:i know you will never let people know its details but can you at least make a youtube montage to let us know how does being invincible like?
I will not post any videos but Others have posted battles with our characters.