Katara, the Fearless

Replacement effects are unaffected by Katara's ability. For example, an Ally that enters with one +1/+1 counter on it won't receive an additional +1/+1 counter.

Triggered abilities use the word "when," "whenever," or "at." They're often written as "[Trigger condition], [effect]." Some keyword abilities, such as prowess, are triggered abilities and will have "when," "whenever," or "at" in their reminder text.

If a triggered ability is linked to a second ability, additional instances of that triggered ability are also linked to that second ability. If the second ability refers to "the exiled card," it refers to all cards exiled by instances of the triggered ability.