Wound is an ability that causes the damaged unit to get wounded, in which wounded units will have all heal, and regenerate health being cancelled out. In details, all health restoration that is applied via regenerate or by heal (even by another aly unit) will be cancelled out. However, the heal ability on a wounded unit is not disabled, and it can still heal other unwounded allies if they are not wounded too. If a wounded unit uses heal to itself there is no effect. Drain and Drainbolt abilities are not affected by wounded status, thus even wound units can restore health using the latter two abilities. Wound inflicting includes a blood ball sending from attacker to defender, drawing a wound on the victim card and finally applying it on the health heart of the card. Health increase due to protect, Health Plus are not affected.
Call of blood has wound all ability but the animation is much different. In fact since it is Blast + Wound all in actual card descriptions, it is shown as blast animation and then wound animation, without the blood texture balls. It looks like a blast spell gives wounded statuses and 1 damage.
Wound is status based, so it can bypass physical defense and cannot be inflicted to immune units. However it will not trigger reflect. Even call of blood will not make reflect useful, as the card is actually a spell which reflect finds no caster to deal damage with.
Call of Blood[]
Althought the description of the ability says wound all enemies, the detailed description is "deal 1 damage to all enemies and cause wounded status to them." Thus the card ability is Blast + Wound all, rather than wound all alone.