[Jurri]

Maybe I'll summarize the structure of this part of the turn, based on how I understand it:
1) Mages cast spells in random order. This can mean that an enemy casting seeking arrow on the province your mage was when casting teleport could still hit the mage. This phase is of special importance if domes are being cast in the province. Magical assasinations happen at the time the spell is cast, so the victims won't partake in any battles if they die.
2) Astral Corruption triggers, if active. Yes, this happens before any "scheduled" battles take place in the province.
3) Teleporting forces and forces that were previously hiding in the province or neighboring provinces attack the province. If multiple nations have units coming in, the order of the attacks is the same as in the regular battle-phase. The teleporters will again only attack outside the castle. Note that in a siege, the defender's teleporters appear inside the castle.
4) Neutral magical forces attack the province. Spells cast by different players stack. Note that this phase is distinctly later than the spellcasting. This means that every teleporter of the province owner will be in the province already, with default orders (defend/siege depending on the situation). This means that you can't teleport forces into a province you own to defend it if there is a castle present, as the forces will remain inside the castle. The neutral forces only attack forces outside castles.
5) Retreating from the magical battles happens. This can mean that an army will partake in multiple battles in different provinces during a single turn. Also of note is that even if you secure retreat routes during the mundane battle-phase, if you have forces that retreated in the magical battles and didn't have a retreat route they will die.
6) Assassinations occur.
7) Regular battles/movements occur. Note that all units move at the same time; this means that movements between friendly provinces can't be intercepted in this phase. There's a chance that two armies belonging to different sides and moving to each other's starting point collide.

EDIT x?: Edited yet again to make it more clear/correct. Damn you atul for making me realize the error in my ways!