Paralyze

[NTJedi]

Took down one of the computer opponents during a multiplayer game... but it was a surprising battle:

Day_60... The pretender was in his castle and level_6 water and level_2 astral. He never casted any water spells... he just kept doing paralyze. The worst part was he was able to target all my largest creatures. First my elemental king then my pretender then my Khrianic Lions.
I had over 100 stupid small units which never got targeted by his spells. In the end I did win the battle but the battle left me with questions.

2 Questions:

What can be done to stop paralyze and other astral spells?
My pretender and elemental king had very high mg-resistance yet were paralyzed instantly.

How was the computer opponent able to target large monsters with his spells?
He never paralyzed any of the hundred different weak units... his magic casts always targeted my biggest/strongest units. My spellcasters seem to select random targets.