activeselective | Constructions with ‘ia’ and ‘va’

I was wondering how it exactly works with the articles 'ia' and 'va'.

I understand this:
  El ia come - She has eaten
  El ia debe come - She had to eat (had to eat yesterday)

How about this:
  El debe ia come - She must have eaten (right now she must have eaten)

In other words, is 'ia' a verb?
(a special verb like 'debe' is - a verb that leads to the next verb)

Thanks
(i am only a started - subscribed to your group today)