Design-wise, this is a great entry, but it isn't the most notable aspect (in our opinion)
It might even be good to take advantage of the fact that it is a Legend itself and use it as your Commander
However, it can convert only once when that happens
Whenever a creature would die, its controller may its mana cost, if that player does, they may return it to their hand as a replacement effect
just proceed to any Club lounge and speak with the receptionist to activate this feature
And last, but certainly not least, are the Oltec, the living ancestors of the Sun Empire who live in a highly advanced communal society with a direct connection to their gods, as Miguel Lopez, a world-building designer on the expansion, described them in a presentation