UPDATE 9/27: Riot Games has published a new Champion Roadmap that provides updates on everything discussed in the previous roadmap, sans the grappling mid-lane marksman, who was released as Akshan, and Dr. Mundo's VGU, which went live on Patch 11.12.

In addition to further progress shown on Udyr's VGU, Riot Games confirmed that its electrifying bot lane marksman and witty, charismatic support would be released in early 2022, instead of before the end of 2021 as initially planned.

While the initial plan was to release six champions per year — one in each role except mid lane, which would get two with one being focused on skirmishing and mobility while the other would be a more conventional mage — but the timeline has changed due to the champions not fitting properly into a planned event at the end of the year. The champions were initially intended to go along with Gwen, Viego, Akshan, and Vex, but it seems that the concepts have changed. 

Riot Games also stated that they would be introducing Art & Sustainability Updates as part of their champion roadmap. While not full VGU reworks, ASU's should keep older champions up to date with how League of Legends changes over the years. Riot's last ASU was unofficial — Alistar, in 2015 — but the introduction of the ASU process to the Champion Roadmap is intended to standardize the process and contextualize it within the big picture of the developer's next steps.

UPDATE 6/29: Riot Games has revealed more progress on the Udyr rework, particularly in the cosmetic department with a series of new sketches. 

Original story:

Riot Games has released a new League of Legends Champion Roadmap that covers three main categories: the early concepts for Udyr's in-process VGU, the finalization of Dr. Mundo's Rageborn Mundo skin as the last piece of his full VGU, and a revealing of new details surrounding the next three champions coming to Summoner's Rift, as well as those champions' potential relation to Viego and the rest of The Ruined King saga.

In the update, Riot Games' Lead Producer of Champions Ryan 'Reav3' Mireles stated that a full update entirely dedicated to Udyr's VGU would be coming in the next few months, but due to being in the early phases of development as the project was launched only at the start of the year, six potential visual concepts for The Spirit Walker have been shared in the interim. The sketches, drawn by  Justin “RiotEarp” Albers, are being shared with the community for a test reaction.

Riot Games has been working on Dr. Mundo's VGU for quite some time, including the Madman of Zaun's slew of cosmetic alternatives in the form of ten skins, and with the completion of Rageborn Mundo, the VGU is entering its final phases. 

Riot Games showed off the Rageborn Mundo splash art, as well as a YouTube preview of Corporate Mundo. 

The bulk of Riot Games' most recent Champion Roadmap was just that: a roadmap for the next set of champions coming to Summoner's Rift. One of these champions, like the most recently released Gwen, is tied into the story of Viego. Gwen's relation to Viego has yet to be revealed despite The Hallowed Seamstress' release having occured earlier in the month, but the new champion, a mid lane mage, is apparently very integral in The Ruined King's storyline.

The other two champions in line to be released in the near future share two similarities: neither seems to have any direct association with Viego, and both are marksmen. One of the marksmen is being designed specifically as a mid lane champion and is equipped with a nifty grappling hook, and is the Sentinel of Light briefly hinted at in previous champion roadmap updates.

"While champions like Lucian, Corki, and Tristana have seen play mid, none of them feel like they were made specifically for that position, with the traits you often see from champions in that lane—like intentionally-designed roaming patterns and a dueling focus," said Reav3. "We felt a marksman designed for mid would both add a unique champion to the roster and could also be pretty appealing to a lot of mid lane assassin and skirmisher players."

The other marksman is more traditionally molded to the bot lane, and according to Reav3, will give "players an electrifying glimpse into one of Runeterra's most tenacious regions, one that never knows when to quit." The order in which the new champions will be released, as well as the overlap of these releases with the Dr. Mundo and Udyr's VGUs, has yet to be specifically determined to the public in terms of release dates.

All images by: Riot Games