From where aztecs get 2 skull knight at min 6? and what does the warchief do on his aura at min 6?

i was rushed very hard

Aztecs can get skullknights from aging up. theres only a few but theyre very strong units.
The aztec aura grants them 2x exp for killing units when near the warchief, this allows them to quickly get a lot of shipments. This aura can be upgraded at the community plaza to grant 3x exp.

Skullknights are quite slow for melee infantry, they only have 4.00 speed. They are heavy infantry so archers and skirmishers deal bonus damage against them.


is there somewhere in the game that explorer gives 2x experience on his aura?

No thats only for the aztec explorer.

but where i read that? i havent found it.