to understand this skill, Konan (Christmas/Winter) need to be team up with Nagato (Christmas/Winter) in your lineup

Nagato standard attack will summon either Rhino, Chameleon, or Dog of Hell (all these summons are non-ninja unit)

each of these summon have different abilities in terms of standard attack & passive

even each of them has specific trigger skill when these summon died (either by attack from opponent or killed by Konan trigger skill)

so, u should understand by now, team up Konan & Nagato will make full use of Nagato summon trigger skill when summon died

To understand easier:

1. Nagato standard in round 1, summon come out.

2. Beginning round 2, Konan's passive "Christmas Present" trigger. If Nagato's summon STILL ALIVE during this round (which was summoned from previous round), it will be detected as NON-NINJA UNIT.

3. Konan's passive "Christmas of Angel of God" will trigger. This passive will kill Nagato's summon & the team will get specified buff (for example if Chamelon is killed, Nagato/Konan or if u have Yahiko also, all will get Hidden status & mystery become unavoidable)

Other summon will have different buff once they are killed

If Nagato's summon is killed (same round when it was summoned) before Konan trigger her passive (which is beginning of next round), Konan will not trigger Christmas of Angel of God passive. Self explanatory right?

4. Nagato standard in round 2, will summon another one.

5. The step 1 to 4 will be repeated.