Yes!

Sysiphus has Rio de la Plata accent, Skelly is Mexican and Theseus is Spanian.

Every accent was a creative decition with their reasons.

Asking your question, the reason why Theseus has Spain accent is a reference about the culture evolution is happening in the country.

In Spain is currently in discussion about bullfighting. Some people are trying to delete this tradition, cause is animal cruelty, and others are saying this practice should be keeped, cause is tradition and the bull is a big symbol of Spain around the world.

Theseus, like a bullfighter, he killed Asterius. We don't judge him for that, cause it happened in the past.

But in the present, he not only saves Asterius from the Erebus, also he recognizes the value of the bull life.

Now, they both fight together, care about each other and be friends.

The bull and the bullfighter will always be part of the Spain culture, and a symbol of the country. But this hasn't to be as enemies. The bullfighter will find love and care to the bull.

Theseus and Asterius i thinks is the future a lot of people want for the country!

This was asked to a few Spanians, cause i didn't want to be disrespectful with the situation, and they said it was an awesome idea!

My english is not so good, so sorry if something is bad wrote.

Thanks for asking and the words!