How about a fic where the Fenton portal was opened in like the 90s and so Phantom was the literal First Known Hero. Which is why he was hunted and there wasnāt any law to stop the Anti-ecto acts. And when Phantom Planet happened, he just disappeared, or retired. He went to Gotham U for uni and meets Bruce Wayne there and they hit it off as good friends and later wild romance partners who slept around. And when they graduated they separated to do their own thing but Danny returns once in awhile to visit Bruce.
They also meet randomly when Bruce goes on work trips in random countries and cities. They never mention the kids and Danny doesnāt know about Batman. Bruce doesnāt know about Phantom. He just thinks Danny is an engineer that travels for work. Which he is, but heās also mainly the Ling of the Infinite Realms and appears in other countries and cities bc thatās conveniently where natural portals are spawning.
What Danny doesnāt know is that since heās taken up the mantle of king, the zone has changed to match him. So itās much more welcoming and natural portals spawn where Bruce is bc he lowkey is in love with him and just doesnāt realize it. And vice versa, Bruce is lowkey in love with Danny and they fawn over each other when they meet up without realizing thatās whatās happening. But Alfred knows, heās known for awhile. And so does Jazz.
So when one day, Alfred brings up that Danny is in town in Gotham and Bruce says to set a time for them to meet, one of the kids hear this and they wonder who this Danny is, bc theyāve never heard his name. It becomes a Wayne Mystery when that week, Bruce is out most nights and portions of the day and comes back looking happy and soft. Which freaks everyone out and they stalk Danny and realize theyāre meeting each other and this man is someone Bruce cares about a lot. So they bring him up at dinner one day and Bruce is like, oh yea heās an old friend of mine. And when pressed on why they havenāt heard or met him, Bruce just says that theyāve never brought it up and since Danny isnāt around a lot, and Bruce is a little self aware of himself at this point, doesnāt want this relationship to affect the kids since they arenāt exclusive or together really.
So the kids plot and get Danny to come to the Manor for dinner. They then realize during dinner, watching Bruce and Danny interact, that holy shit, this is their other dad. Theyāre so in sync that they donāt realize it and heās so good with the kids too and Bruce is so happy when heās aroundā¦
Cue the batfamily kids Parent Trapping the two, with the help of Alfred who is all for it bc he likes Danny.
In the end, Danny decides to stay at the Manor and the kids can now call him other dad, or pops, or some variation. But they all collectively donāt mention the vigilante side they have, since they all figured it out themselves. Their new dad can do so too. Which then spirals when all of the kids Omarās out on Patrol, Alfred is on Vacay, and Danny is alone in the house when Talia comes a knocking, bc she knows that Danny has always had Bruceās heart and wants him gone. Sheās always been jealous of their relationship so she tries to kill him. The family realize whatās happened when Damian sees some League members watching them on patrol and they race back home to see Danny decimating the assassins and Talia. He sees the family in their costumes and thinks, oh wow this makes all the sense now.
And they see Danny as a ghost, which Bruce recognizes as Phantom, the first hero!!!! And they all sit down and talk about it.
Thereās probs more too but thatās all I have rn.