Undead Jailer

Undead Jailer has Firststrike as long as it has a
Hollow counter.
{1}{r}{t}: Undead Jailer deals 3 damage to target creature or player. Activate this ability only if
Undead Jailer has a +1/+1 counter.
The Jailers are wrapped in bandages. What lies
beneath? Have they been burned by their own
flames, or are they hiding a darker secret?