I was looking around for this and could not find the answers first 1 is Herald of Cosmic events a spell or ability if it is a spell can a a Chaos player Glean Magic it ? also what is it casting level for dispells? 2. It says he rides a Palamquin just like the slanns but could be placed in skinks rather then TG's can i put him in TG's anyways?
1. Herald of Cosmic events is an ability, not a spell. It can't be dispelled or copied. 2. You could put him in a unit of temple guard, but he will be in the front rank and loose his sight bonus.
Basically his Palanquin follows the same rules for a Slanns. And if you read the Slanns it clearly states that if he is in a unit of anything except temple guard, he acts as normal in the front rank and looses his large-target sight range. For tetto'eko you just replace the wording of "Temple Guard" to "Skinks" therefore making temple guard one of the "other" units that causes the Palanquin to loose its effect. (Except the ward save)