Eclipse Existence (Blue)

Whenever an attack you control hits a Light hero this turn, you may banish a card from their soul. If they do, they lose 1

.

If you have more

than an opposing Light hero, you may banish an action card from your graveyard.

If they do not have a card in soul, the attack would be unable to banish a card therefore they would not lose 1.
The green symbol on Eclipse Existence is life.
They only lose 1 if a card is banished from their soul from Eclipse Existence’s effect. If a card if banished from their soul from another effect it will not cause them to lose 1
The second effect of Eclipse Existence happens as the card resolves. You must choose whether you want to banish an action card from your graveyard as soon as Eclipse Existence resolves.

Cost0

PitchBlue