Sentinel

Sentinel is a new Ability introduced in the Unearthed Prophecy expansion. Only these three factions have Sentinel minions: Abyssian, Songhai, Vanar.

Sentinels have two forms – when you first play your Sentinel minion it will appear on board as a Watchful Sentinel token, waiting to transform. Unless your opponent triggers the hidden condition listed on your Sentinel minion, it will remain a Watchful Sentinel token with no effect. Only your opponent can trigger your Sentinels (and only on their turn), however only you know what they transform into!

Watchful Sentinels can not be dispelled! Dispel only works after the transformation!

There are three hidden conditions on which the Sentinels trigger:
 * 1) General attacks: The enemy General attacks.
 * 2) Minion summoned: The opponent summons a minion. (Need not be only from the action bar. Ex: Pax on its death triggers this sentinel when it summons Iron Dervishes.)
 * 3) Spell cast: The opponent casts a spell. Bloodbound Spell counts as a spell too.

The sentinels can only be transformed on the opponent's turn. Just as for any other transformation, any buffs applied to the sentinels are lost when they are transformed.

Interactions

 * Spells creating minions (e.g. Wraithling Swarm) proc both spell and minion sentinels.
 * If you have a Sentinel or Build minion with a buff applied in the action bar (say via Phantasm), the summoned token won't be buffed, but the buff will appear when the minion transforms into its true form.

Spell Sentinel
In general spell sentinel interactions follow these rules:
 * If your spell targeted a spell sentinel directly with a destroying effect, it WILL continue its effect past the transformation. Like Natural Selection, Martyrdom.
 * If your spell targeted anything else - a Wraithling, a tile - anything - the spell will fluff. See Ritual Banishing, Plasma Storm. This manifests in strange ways - Moonlit Basilysk is treated as a 2/2 'base' so it dies to Plasma Storm. Ritual Banishing just loses its target and does nothing.

Dispel spells like Chromatic Cold, Sun Bloom, Primal Ballast and Siphon Energy have special interactions with Spell Sentinels:
 * Dispel triggers the transformation when cast, thus the dispel actually hits the 'base' activated sentinel. The game then reads the sentinel as dispelled, thus its effect does not fire.
 * So if you cast Dispel spells on an Mind-Cage Oni/Xerroloth when they are Watchful Sentinels, their effect doesn't proc. But if you cast these spells on an Mind-Cage Oni/Xerroloth when they are transformed and active, they get to trigger their effect once before being dispelled.

Minion Sentinel
In general minion sentinel interactions follow this rule:
 * If your minion's Opening Gambit (e.g. Lavaslasher, Bloodtear Alchemist, Arclyte Sentinel) is manually targeting it will kill the sentinel, the effect works on the sentinel itself pre-transformation, so the sentinel dies and doesn't transform.
 * But if the Opening Gambit is automated (e.g. Dancing Blades, Sunset Paragon, Blistering Skorn) it will deal the damage after the transformation.

There are also interesting interactions:
 * Sandswirl Reader's Opening Gambit on a Freeblade returns a Watchful Sentinel Token to hand, but you still get a Freeblade on board and it switches places. If you play the returned Watchful Sentinel Token from hand, it won't transform because it is only a token and not a real Freeblade anymore.


 * Transformations won't trigger Sentinels. This includes cases such as a Build minion finishing building, or an Egg hatching.