all heroic spirits are enhanced by belief and their legends, truthful or not...

As Limbo dies there... his life blood claiming the ground beneath his body, the holy grail detected and reacted to his death, doing what it was intended to do upon Limbo and making his secondary body appear in thin air, transfering his soul... he stays there...floating in the air...then came a booming voice from the grail, being forced to read the belief of the tenno and the warframes. Everyone herd the voice around them, like a huge lightning hitting the ground.

-GODS CASTS IN STEEL AND FURY, STRIKING THEIR ENEMIES IN A WAY THEY COULD NEVER COMPREHEND-

Then...there was silence... Gilgamesh could only stare in horror as he hears Limbo's legend.. every word the grail spoke, his eyes widen in fear of fighting a god... this... this should not even happen, it's impossible! But he realized that he nearly killed this god while he was alive. So it means that his Legend was just a myth! He steeled himself to kill this fake god.

Limbo fell down to the floor, his real body dematerializing on the ground by the void, claiming his body in the heartless abyss. But for the very first time, in the very first day he was summoned, he can feel his strength back up to his peak, his power, came back to him in waves, it's like he was back in his world! But...before that...he looks at Gilgamesh with a blood lust that can rival a Valkier... his power spiked and summoned a cataclysim without the need of clapping his arms, Gilgamesh was inside the cataclysmic sphear of death then foolishly attacked him, summoning his swords. He stopped time just before all of Gilgamesh's blades struck him...he hums, taking his time in the world, Looking at a weapon that interest him. He then spotted an elegant sword. The fuller qas colored white, it's sharp edges was colored green, the Grip was wrapped in red cloth, the hilt was shaped like any normal Galatine swords, the tip of the spike like horns of a galatine was sharp, it was also ornamented with a beautiful Emerald at the end of the grip, the pommel was shaped like fire. He felt it radiating with power, a locked potential that has yet to find it's rightful master. He held it... whatever was holding this sword to fulfill Gilgamesh's will broke. Then, the flame like pommel ignited aflame in the colors of the Void, no one can see it but him, the emerald shines and filled with the void, Recoloring it into a golden gem with rays of light dancing inside it, he felt it, the Weapon accepting him. The grail then spoke again once more.

-MASTERS OF GUN AND BLADE-

Then... he charged and ruthlessly slicing off Gilgamesh as he made scars upon scars upon scars unto him. He won't kill him...yet... he was doing this just to make him suffer...he knows he stopped time...but he knows that his mind is still there...

And then with Limbo's Void and the Holy Grail sucking his energy, something formed. it was Limbo out of his Warframe...but... it's actually the man in the wall, complete void dark eyes and sharp teeth.

Hello, Kiddo...
The man in the wall...what do you want
I don't know, nor I don't care, Just wish for something so I may return.
THEN GET THE HELL OUTTA HERE!
Ok then kiddo, But first... let's put you and your friends in something far more familiar to you... *Chuckles*
NO, WAI-
Bye~ Pop!

Excalibur: Hmmm hmmm~ (Humming the second dream music while cleaning his sword)

POP! -T
WHA WHO WHERE! Oh... GOD DAMN IT LIMBO I ALMOST CUT MYSELF!
Everyone: Uh... *Sweat drop*

its touhou so I rate this 100/10

Stop it with that (O) thing it’s annoying and it ruins the flow of the story.

Wonder how Saber would react to Excalibur.

Fishing with Lancer?! You almost had me there. The fight was okay for Limbo. Try to show other frames too. Limbo can be overkill at many points.

Yay Lancer did not die. On a side note, a servant should feel something wrong with a Tenno due to void energy. And forming a contract might have side effects from a simple headache to being driven mad due to exposure to void energy. Although it can be mitigated by converting void energy into mana (similar to how most Warframe abilities work like Exalted Blade, Embers abilities etc)

Really interesting idea. As someone who is a fan of both the Nasuverse and Warframe, I am planning a crossover between Warframe and Fate/Apocrypha. But it'll take time since I got to finish my Warframe story first.

Anyways, first off, I'm glad you are considering the nature of the void in this fic instead of dismissing it as just another form of magic. The void is something that can distort natural laws of physics and even bend time and space with its presence. Even in the Nasuverse, it can be considered something alien. Even more when you consider the law of higher mystery negating lower ones. So no doubt magi are going to go nuts over it.

And then we come to the Tenno and Warframes. Even when not summoned as servants, Tenno can still pack a punch. Warframes can be consider to be strong as servants with low-mid tier parameters (STR D-C, AGI: C-A, END: C or something similar to EMIYA.). But they don't have something comparable to powerful noble phantasms that servants usually have. Even then, they can still be menace if the operator knows what he is up against and plans his actions well. Assassinating masters is a viable strategy thanks to stealthy Warframes. Plus operator can even take it up a notch using Void Mode, which is similar to rift walking as Teshin calls it "walking between the folds" in The War within. And Note that Tenno can probably harm servants thanks to void energy. We know that any weapon needs mana to hurt servants. Along with void energy, Tenno can do it by channelling energy into their melee weapons. As for guns, they don't allow channelling in game. However, we do find Tenno carrying many tech weapons against Sentients who can supposedly take control of advanced tech. My theory is that some amount of void energy comes into contact with them, preventing sentient control. So ranged weapons could work to. Although Servants will greatly outrange and overpower them.
As for Limbo, he is OP. 20 seconds to time stop is more than enough time to kill most servants as long as the Tenno can hurt and kill them. Plus indefinitely staying in the rift. Total cheat since there it exists "nowhere and everywhere."

And as servants, Tenno can be a HUGE threat to even top tier servants. It can be compared to true archer from Strange fake who has high parameters backed by insane versatility thanks to his 12 noble phantasms.
If you are thinking about giving skills and NP, I do have some ideas:
Traits: Human, Demonic (Void demon), possibly divine if we consider the case with Altera.
Personal Skills:
Self Modification (Equipment, Rank EX): Basically the mod system. Allows the Tenno to modify the properties of weapons and Warframes.
Eternal Arms Mastership (Rank A): Self Explainatory why Tenno can possess it.
Teachings of the Tenno Schools (Rank ?): Abilities gained from the focus schools Tenno master. Gives various passive abilities.

Non unique abilities can include: Golden Rule(because of loot), Eye of the Mind (False), Innocent monster (due to how Orokin viewed Tenno before the old war)

Class abilites: Independent Action, Item construction (Foundry)

Parameters(Operator/Warframe):
STR:E/ B
AGI:D/ A
END: E/B
MP: EX (Because the Tenno might find a constant supply of energy from the void)
NP: EX
LCK: E~C.
Noble Phantasms:

Most weapons: Rank E-C. Still can be deadly due to mods

Paracesis: The Sentient Slayer(Rank B, Anti Sentient): A sword that is also capable of doing void damage is no doubt something of great mystery. You can make it a close range weapon or a typical Saber beam when true name is unleashed.

Second Dream: Dream not of what you are, but what you want to be (Anti Unit, Self, Rank EX): Noble Phantasm derived from the sleep the Lotus placed the Tenno on after the old war. Manifests in the ability to change Warframes at will.

Zariman Ten Zero (Rank?): A reality Marble of the Zariman incident that resulted in the birth of the Tenno.

For scenarios: You can try Apocrypha for it's roster of servants. Stay Night or Zerois good too. If you want to try FGO, then Camelot is a good singularity (Banish Gawain to the rift, How the round table would react to Excalibur or Galatine Prime XD). Another thing you can do is create an unique scenario or singularity like the events which leads to Tenno forming a contract with Fujimaru and joining Chaldea. Also Fate/Extra can be fun. You could even have Simaris involved in the moon cell.
Anyway let's see how this goes.

Yes! I would like to see that very much!

Well, he gotta check out Einzbern Castle for once. but it's gonna be interesting to see what's happening in the temple as Caster is already deceased.

Sweet Limbo

fucking limbo mains and their jojo references...i should have seen this coming miles away.

Also, dude, quit it with the '(o)'s.

So why is the tenno going along with this, the Void would burn out anything the grail could try so why is it acting like a Ruler?

Ok you have my attention good job so far