Hi,

rulebook says that 'None of the creatures, Enemies, or Draconic Lords in the Inner Region can be affected by any Spell, nor may they be evaded.'

But can my follower fight in my place ?

And from the other hand when I am fighting against Eagle King 'Fighting the Eagle King is conducted according to the normal rules governing attacks, save that the Eagle King cannot be evaded and only characters may attack the Eagle King; Followers, Spells, or Objects cannot fight in a character’s place.'

Can I cast Weakness on Eagle King ?

I believe you already know what you're asking…

1) Why would you even want to have one of your followers fighting for you? - Is there any one strong enough to beat the enemy? - I don't think so.

But just to be clear - you can't have a follower fight the Highlands Eagle King or Dungeons LoD for you - I believe you can have them fight for you in the inner region - but I don't see why you would want to do that - unless you only have one life left and want to make it out of there alive.

2) You are talking about the alt. Ending with the Eagle King, right? - If yes, the answer is no, you can't cast Weakness on him.

If you're talking about the Highlands Eagle King, the answer is yes, you can cast Weakness on him.