The Overlord family reunion/Gorog explained his idea to his father

Here is how the Overlord's family reunion begins in Son of the Overlord.

Then, the Overlord was enjoying his family reunion.

The Overlord: It feels good to be back!

Gorog: Good to see that you're back, Father!

Then, Gorog came up with an idea of his own.

Gorog: I have a plan for our revenge against our enemies.

The Overlord: What do you have in mind?

Gorog: Well, I was thinking that we should bring the mane heroes to join the dark side.

The Overlord: Excellent, I love it.

Lord Vortech: What are we going to need to prepare or our plan?

Gorog: We'll need enough evil alliance from Ninjago capable of ruling it!

Lord Vortech: They're all here, Gorog.

Nadakhan: Yes, we're all together thanks to Lord Vortech!

Acronix: With your father returning, we're ready for our revenge!

Krux: For the sake of the darkness!

Scorm: And for our own prize to claim!

Spinlyn: Chima!

Lord Vortech: And all other worlds to take over!

Gorog: Yes, let the games begin! (laughs evilly with everyone)

At last, they make ready to begin their first move.