Hero's Monument

Hero's Monument
Legendary BuildingMonumentCost: 5ATK: HP: 6
Arrives: Summon an 8/8 legendary white Ghost token named "Daigo Stormborne." He's indestructible, untargetable, and unstoppable, but can't patrol. Trash him when this leaves play.
Your heroes get +1/+1.
WhiteDiscipline Tech III

Untargetable Rulings
Something that's untargetable still CAN be attacked. It can even be affected by some spells and abilities, but NOT spells or abilities that use the [target] symbol. — Sirlin
Indestructible Rulings
If an indestructible thing has 0 HP because of having -1/-1 runes, it will remain exhausted forever. If it gets any damage or attachments in this state, immediately remove the damage and/or attachments. — Sirlin
Attachments are cards that attach to a unit or hero, like "Spirit of the Panda" or "Entangling Vines". Runes and other ongoing spells or effects are not attachments. — Sirlin
Even if it has -1/-1 runes that were from something that "dealt combat damage in the form of -1/-1 runes," you still don't remove them when the indestructible thing would die. — Sirlin
Some effects like Obliterate, Sacrifice the Weak, and Death Rites ask a player to destroy or sacrifice the unit that is the least according to some ordering. These effects skip units with Indestructible and units that cannot leave play. — sharpo
Unstoppable Rulings
Having a detector (or a Tower add-on) doesn't help against the unstoppable keywords. Even then, unstoppable attackers can ignore patrollers. — Sirlin