I think the Tower was made by Phanta to artifically create new shining ones for him to turn into jewels with shinwonryu being key to the process
How is "shinwonryu" being the key to such a thing? The rest reminded me
@Ray Barracuda 's prediction about phantaminum as an alter ego of SIU or something.
Could the tower be made by darkness? Darkness created Phanta from the tower? In the old lore, I heard Phanta was a normal one before he transformed into an axis iirc. Maybe the tower role is to make someone strong enough to defeat Phanta and bring peace.
I find this unlikely. In general, we don't know the exact time span. We can be sure Urek is younger than tower. We also know that Phantaminum came, killed some HRs of Zahard and disappear, and this may or may not coincide with Urek trying to "chase" after him. The most plausible scenario from what I have seen is that (even if we assume Phanta was escaping or hiding or disappearing from Urek's side) tower is another entity than Phantaminum. He went there, and would not like to be bothered with tests or restricted by rulers or admins with anything at at some point, killed some, then, he was referred to Zahard, and Zahard talked his way out. He would definitely not take floor tests. Maybe Zahard learnt to make jewel seals from him and we will be introduced sealing in ToG more properly.
If Phantaminum creates a huge ass tower with such drama(653 chapters, years, fandoms, you know), he should not be someone that can be chased on foot by Urek...
It may also sound sort of funny but a literal "darkness" of the tower would probably react differently to Urek, in lieu of some Headon comments. The only darkness in the tower is Luslec, and he is not the literal darkness as we know.