You want him to deliver this thorn directly into the hands of who? Baam is not coming for a thousand years.
You also said he killed all these people out of anger but he sure did not look angry. The survivors described it as beautiful. That does not sound like someone in a rage. You also seem to equate his OP with the thorn and even go so far as to say "without the thorn, which I can't stress enough he didn't seem to deliver, he is probably not quite as op as he was against the admin." However, there is absolutely nothing in the story or imagery to suggest this. Quite to the contrary, he is ranked #2 which is pretty OP. That thorn was meant for Baam and we can't even say if anyone, such as Zahard himself, can use it. Karaka even wanted to melt Baam down to gain access to the thorn. When we see Enryu in all his glory attacking, we do not see any evidence of him using the thorn.
There is no discussion of Enryu outside of the FOD. There is no indication he even climbed the tower at all. He came by way of some special door and just disappeared. The only suggestion that he is in the tower is the fact that Headon is said to be looking for him. For an admin who can go anywhere, this seems rather remarkable that in a thousand years he has been unable to find anything about Enryu. Personally, I think the power of Enryu is equivalently in the thorn and Enryu has left the building the same way he entered. That was his mission and it has been accomplished. However, if Enryu was to re-enter the tower, for whatever reason, I am certain Zahard would regret picking a fight with him and Zahard would be squashed like a bug.