Experimenting on yourself is not safe.

This is an AU where Frankenstein ended up contaminated with corrupt noble energy resulting in: some physical mutations; not being able to just walk up to Central Order Knights like a Kertia Boss... Ahem, Clan Leader as per canon since they can sense noble energy; and occasional episodes where he gets hit with an addiction-type craving to drink someone's blood and channel the energy into them. (Fortunately animals work.)

That craving is a way of justifying M-24's behavior in his first scene, which doesn't fit with what's established about him a bit later. If every so often he just needs to infect someone, and M-21 is used to that being a thing and cares about what his fellow M-series needs more than random people, that'd explain why they're both so ok with it.

By the time Franken hits Lukedonia he's probably had two hundred years to try to fix or limit the damage, so he looks about as human as nobles do instead of looking like a mutant and the episodes hit rarely (and can be headed off by drinking blood from one of the nobles he's experimenting on – they don't stay bound or turn into mutants, so it's safe to use them to earth the charge). Dark Spear makes episodes even more dangerous.

I may turn this bunny into a full fic, but if so I'm going to handle Franken and Rai's first meeting differently.

The red eyes that met his own were ancient behind the mask of noble reserve this person wore. Yet they were also mildly curious, and somehow innocent with it. Had he never seen a human before?

Cadis Etrama di Raizel lifted his palm.

A cut appeared in the middle of it. Had he slashed his hand with whatever power changed Frankenstein's clothing?

Red. Red on pale skin that seemed to have very little sun, even though nobles weren't troubled by sunlight. No, that was only the pitiful mutants, a curse inflicted on humanity by noble selfishness.

And human greed for power.

The noble who gave him sanctuary held his hand out, offering, as Frankenstein stared.

Shelter, clothing, denying the noble Lord what he wanted. Now this?

Perhaps drinking blood was casual among the nobles, since it didn't compel them?

If he drank, then he would have some sense of where he'd landed himself. What kind of person this noble was. If it was safe to stay here with this quiet, ageless youth.

Was this a trap? He'd studied captured nobles, but he didn't have complete knowledge of the abilities unique to the most powerful. Yet from all he'd heard, you couldn't control someone by giving them your blood. It was the one whose blood was taken who was putting themselves at risk.

The way Cadis Etrama di Raizel was putting himself at risk, by giving sanctuary to someone called a traitor, murderer, criminal.

"Bread and salt?" Frankenstein asked, taking the hand and stepping forward. He held the palm to his lips, looking down at the young man for permission.

He nodded.

"I'm not required to reciprocate, am I?" Frankenstein asked, just to be sure. "A human who has their blood taken by a noble… I've seen what happens to them."

"No," Cadis Etrama di Raizel told him. It was only when his eyes grew distant again, the way he had looked when the other nobles spoke, that made Frankenstein notice that the noble was focused on him until then. "I do not want to see you consumed by the hatred you bear."

Frankenstein hadn't lost that reckless tendency to experiment with himself. What was one more risk to take tonight, when he'd fought two clan leaders and summoned Dark Spear? Expecting sanctuary from a noble was madness enough.

Caution thrown to the winds, he did not touch a finger to the blood in the cupped hand to taste it, or even lick at it. He pressed his lips to the wound, as though he kissed a lady's hand.

Oh.

He didn't tear at the wound the way a mutant would. He didn't try to devour the blood, drain Raizel. It was enough to simply sip from the trickle.

It was so much more than simply enough.

Raizel was innocent the way a sword was innocent: he knew only one thing. Yet he knew that wasn't enough, wished he had another way to perform his duties, but despaired of ever knowing enough to find such a way. He lived for his duty, he could not seek to abandon it, seek alternatives. He was trappedhere, by his own choices and honor, for the sake of others.

Frankenstein was safe here. Safe, with someone who shared his desire to protect no matter the cost to himself.

Relief drained away the energy keeping him on his feet despite the long chase, followed by a battle against two clan leaders and Dark Spear's assault. He found himself sinking down to his knees.

When he opened his eyes, he saw that Raizel had also knelt to keep his hand within Frankenstein's grasp, although far more elegantly. He seemed utterly composed, no trace of feeling that it was a loss of dignity to kneel in front of a human. Frankenstein was only on one knee, but Raizel was on both.

He lifted his lips from the wound, certain that the cut would close. It could only be Raizel's will that kept it open, when nobles healed so quickly.

Raizel's expression was not anything as uncertain as studying him. He waited serenely.

"Thank-" Frankenstein started to whisper, and cleared his throat. "Thank you."

Raizel nodded, and remained kneeling there until Frankenstein moved to stand. He was as utterly graceful in rising as he must have been in kneeling down.

He was… very old. He had a great deal of practice in such movements, after all that time.

Bedrock. Raizel was bedrock.

He was safe here.

He was home.

Bread and salt is a 'sacred rite of hospitality' thing. In a desert or hot climate in general, you need salt to not die.