As far as I know no one really knows what he's doing now, but he's probably still writing some of the new content. The manhwa story more or less ended with the Hero's Trail instances in the Dimensional Gap but there hasn't been a definitive ending to what happened to them all.
TBH I never really liked the more linear sections of RO; it ways felt the game was more meant to be enjoyed as an experience rather than going through storylines with characters and such. Story was mostly delivered in 3 ways: 1. Environmental storytelling, years before Dark Souls made it popular 2. Short conversations with NPCs / reading some books in-game that give some context to what happened 3. Condensed questlines focused on maybe 3-4 characters
My favorite was always number 1 since just walking around the dungeons and trying to piece together a story based on the monsters and the level design is extremely fun. I don't need some NPC with 70 dialogue boxes telling me that some serious shit happened at Glast Heim, I can just fucking see the ruins of a clearly great castle filled with hollow suits of armor and corrupted knights and understand. The NPC conversations usually weren't useless and some story pieces hit harder knowing what they say. The one I usually think about is just how fucked Rune-Midgarts is since the king went missing months ago and all of the heirs were killed by assassins or a curse. The more direct questlines like Friendship quest were good since again they reinforced the underlying theme of the game, that is Ragnarok is already happening and the world is coming apart at the seams.
Brief recap of the world: Rune-Midgards: The king is dead and the aristocrat families are squabbling and scheming over who should be the next king. Literal Satan has resurrected in the desert but is fortunately being kept back by the adventurers. Both the buried shrine under Payon and the various monster islands off the Alberta coast are growing more restless. The mages in Geffen have their hands full containing both Glast Heim and Geffenia, and never had time to investigate the Nameless Island where the king was kidnapped and died. The world tree connecting Umbala to Niflheim is slowly being taken over by the dead. Some tried to enter the wormhole that Satan created, but the world on the other side is just as inhospitable as home. Schwartzvald: The entire nation has essentially been taken over by the Rekenber corporation, who continue to experiment on live humans as a means to try to recreate the heart of Ymir. The scholars in Juno don't care, and are too busy trying to investigate the buried cities of Juperos and Verus underneath, including its fate at the hands of the mad scientist Vesper. The twin cities of Einbroch and Einbech are incredibly polluted, while Lighthalzen continues to segregate the rich and poor. The shrine to Odin off the coast seems to have been invaded by very angry angels, or at least demons wearing their skin. Hugel isn't doing too bad, if you just ignore the dragons who kill everyone near Abyss Lake and massive tower of the great Satan-slayer Thanatos, who is rumored to have come back to life angrier than ever. Arunafeltz: While they have always been generally hostile, the people of the country have gradually fallen to the religious cult that seized control of the church. The young Pope has almost no power while the fanatics beneath the temple are repeatedly trying to summon stronger beings for an unknown reason. All of this was completely optional to the players though. Most RO players just play dress-up and chill with their friends, which is part of the point of the story. The world is ending and no one, not the players nor the NPCs, really seem to care.
But starting around episode 14, the story shifted to adding more and more dedicated questlines with named NPCs and reoccurring characters. Ahat and Cheshire were well received, so the writers started to shift more in that direction. I didn't really mind them too much since the New World was just fun to walk around and kill shit. Episode 15 was where I started to question the design, since Phantasmagorica's story was all over the place and I just didn't really care about the new characters. 16.1's Banquet of Heroes just had too many characters to really pay attention and it felt like they were placing too much pressure on the player, when the game originally just had you be one of the many adventurers in the world. There was a reason that the classes were called Jobs, because being an adventurer was just kind of seen as an in-universe occupation. 16.2's Terra Gloria had some neat worldbuilding but my god was it boring to do. 17.1's Illusion was mostly just a continuation, with all of the same problems but with more brown maps for some reason. 17.2's Sage's Legacy was actually good I thought, since the wide variety of new maps, enemies, and music were all well made. The only problem is that people would just run the instances for gear instead of going through the new maps, so it all felt squandered. I ended up dropping around here, and I have no desire to play through 18 or 19, or the upcoming 20 and 21. But hey, Gravity/Gungho somehow keep making money off the game.
I would have really liked a completely different take on RO, since it has nearly all of the elements of a good game hidden underneath it all. I don't want to play through a character-heavy story and I definitely don't want to play through any of their shitty mobile cashgrabs.