Just Checking In After Transmigrating into a Book Doesn't Make Me a Harem Protagonist, Okay?

You're a transmigration tasker, but instead of transmigrating into one book, you transmigrate into three, becoming a background NPC in each.

After accepting reality, you help the original plot unfold.

For example:

When the main leads meet by chance for the first time, you have to be there to check in. When the main leads realize their feelings and pledge themselves to each other, you have to check in. When the main leads break up for whatever reason, with the usual "he doesn't love me, he loves him, and I love him" mess, you have to check in. When the main attacking lead chases his beloved through a torrential downpour and kneels to beg the main receiving lead for forgiveness, you have to check in...

You have to check in for everything.

Fine.

But can someone explain why your check-in task has both succeeded and failed, and why those main leads turned around and confessed to you?

Have you become a harem magnet?!

Aren't you supposed to be a background character?!

Main leads in Story One:

The main attacking lead is a proud young master, a heaven's favorite. He can't understand why your attention keeps drifting to a totally unremarkable classmate, and he hates that person.

You: ???

The main receiving lead is a poor academic ace. He envies how the school's most popular student council president follows you around and becomes your friend. He wants to be your friend, too.

You: ...

Main leads in Story Two:

The main attacking lead switches careers to become an actor and rises to top-tier stardom...

The main receiving lead is a pure, innocent newcomer...

Main leads in Story Three:

The domineering CEO...

The trendy green tea...

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Note: 1. The main text is written in third person.

2. Harem magnet.

Theme: Everyone is the protagonist.