I'm kind of surprised the art doesn't depict an Archmage (like the one on Bolt of V’Tar) enchanting a Sslak.
Perhaps it's because Sslak/Usslak are Dark/Arcane, and Sentinel of V'tar can only target living creatures and thus is a Nature enchantment. Non-Nature enchantments tend to work on all non-mage or corporeal creatures, including non-living creatures, which would otherwise allow creatures like Talos, Sardonyx, Iron Golem, etc, to be enchanted by Sentinel of V'tar. Still, creatures like Malacoda, Cerberus, Steelclaw Grizzly - even Adramelech - can be Sentinels. Still, it can enchant (U)Sslaks... which seem to be the most obvious Sentinels but I guess that's somewhat redundant considering they already get Unmovable and Anchored when in a zone with a V'tar Orb. Perhaps if the ghostly essence around the lion resembled a Sslak, similar to how all the "{animal} {enchanced-trait}" Nature enchantments show a ghostly creature the target gains the traits of.
