Nick and Hephaestus were the first to officially gain nen abilities with Nick unlocking it by his own effort and Hephaestus getting it unlocked by Nick. As a god with a massive life force Nick accidentally knocked out everyone in the territory the moment he unlocked his as it was uncontrolled and fully extended. He wasn't using it on anyone though so it merely brushed against them and sent them to sleep. It was a bit annoying but Nick needed to go to the realm in order to fully grasp and control his bodies aura.-
He was certain that it was supposed to be harder to master then that but he managed it in less than a day thanks to being able to calculate and quantify the energy using his daedric powers. Nick found it rather funny how it was so easy for him to master because he as a daedra was innately sensitive to life force. Typically not a good thing but in this case it worked out perfectly as it helped him unlock and master the energy in a short period of time. Hephaestus took much longer at about a week of nonstop meditation.-
After that they tested their nen affinities and Hephaestus got transmutation. Nick on the other hand got mixed results. His "human" body was a natural emitter but his daedric body was a specialist as the water turned into steam under it's aura. His true form couldn't even use nen to begin with since he didn't have a physical form technically , no daedra did. The bodies they were seen as were merely containers to house their minds in most cases. Still the difference in nen types between his bodies was quite interesting to Nick as it proved that the mind and soul truly had nothing to do with the power.-
That confirmation aside it also presented a unique opportunity to him that he was rather interested to put into practice. For his "human" body Nick created a single ability with a restriction that it was the only one he could have. He set a few conditions for the ability as well that made it entirely unusable with a single exception , his bodies death. What the ability did was quite simple really , it was a pure retaliation type ability. Upon his death all of his aura and mana in his body would condense into a single spot no bigger than a grain of sand and shoot into the body of the one that killed him before detonating.-
This was a particularly vicious ability because it would only stop working after detonating within the body of whoever or whatever killed his body. This meant that escape was impossible regardless of speed or obstructions. Nick made this ability with Zeus in mind as he was sure the other god was nearing the point where he would come to attack again. Hephaestus hadn't stagnated over the last two years but had slowed to a snails pace on her improvements.-
For Nicks daedric body however he crafted a much different ability that was quite useful to him. {Faithful tithe} was the ability he created and the way it worked was that it allowed him to create a {believers mark} which was a small golden coin with an image of a hawk. The trick was that when the coin was held by someone who believed in him he gained a single counter. There was no limit to how many marks he could make either. Activating his ability allowed Nick to "spend" these counters in order to gain a one time "tithe" of mana which dissolved the marks.-
As far as restrictions went Nick could only activate his tithe once a month and only on the first. He also made it so his aura was reduced to a single percent as well for the rest of the month should he activate the ability. He could have made all sorts of other abilities but this one was what he chose for the moment as his lacking mana levels were severely holding him back. Hephaestus played around with her aura but ended up settling for turning her aura into metal like mercury and called it done.-
Nick couldn't blame her for her lack of interest in the power as it simply didn't scale up to divine levels without so many restrictions that it may as well not be used at all. Even Nicks human bodies ability had it's death as a prerequisite just to be able to reach that level in theory. That's right theory because until it actually goes off no one knew exactly how powerful it was going to be only that it will be very powerful. Nick didn't expect it to kill Zeus or anything like that but he was sure it would ruin the gods day.