The Silver Templars have two stratagems in addition to what they have access to as an Ultramarines successor. At first glance, to me, he seems like an extra character I may not need in an already character-filled army, as Space Marines have quite a few choices they'll want. At a minimum most people want 3, with Chapter Master/Captain, LT, and either Chaplain/Librarian. Adding in an Apothecary as it quite standard, if we add an Ancient we're up to 5 already. Rounding up he'll be close to 100 points, so I'm wondering if he's really worth it. Some notes below:

One battle-brother amongst the Chapter's honour guard may have the distinction of carrying the banner of their Chapter into battle. This is a sacred task, one borne with immense dignity and gravitas. Hellblaster Squad • Eradicator Squad • Aggressor Squad • Eliminator Squad • Suppressor Squad • Desolation Squad • Infernus Squad • Firestrike Servo-turret • Hammerfall BunkerThanks to Mortal Realms Magazine, I’ve had just about enough of swirly ghost models, but this proves that pretty much anything is better with Metal!

Base on how many characters are on this sprue, I find it very unlikely that these would be available in anything other than the Indomitus set. The Captain and Lieutenant could easily be sold as separate sprues, but this is clearly just meant for a large boxed set. Perhaps a “Start Collecting” set, but that would be away down the line. Warhammer 40,000 Indomitus – Judiciar Sephax’s major perk is that he comes pre-equipped with the Benediction of Fury, a replacement crozius that’s S+2, AP-2, 3 damage and can proc additional mortal wounds on 6s to wound. His required Warlord trait is Iron Resolve, which isn’t bad, giving him +1 wound and a 6+ FNP. Ancient Kae

Granting obsec: this is good, but I can easily add Rites of War onto another character, so I don't consider it a unique benefit.