In trying to put some additional promo Warlords on the print sheet at the last minute we all overlooked an OPT statement (on each) that were apparent to and intended by all involved in the creation.
Therefore both Rabinus the Elder and Warmaster Sceth receive immediate errata:
Rabinus the Elder should say: “React: Once per turn, before target character you control…” and
Warmaster Sceth should say: “Order: Once per turn, ready target non-stunned Siege.”
Both these Warlords are not legal in official tournaments at this point, therefore the errata effectively only apply to challenges for now.