Oxyotl also known as He who hunts unseen is a Lizardmen character from Warhammer Fantasy, and is the original badass to invade the Realm of Chaos and run amok for thousands of years (which in the timelessness of Chaos could have very well been billions or more) while causing a massive mess in all the realms and plans of the Chaos Gods. Whether or not he ever met the second guy to do it is a popular subject of speculation among the Warhammer fanbase, though Oxyotl's twice as badass for that fact that he's doing all this without being a bio-engineered psychic superman with high-tech power armor, weapons AND with but his trustworthy blow pipe. A FUCKING BLOW PIPE AGAINST 10 FOOT TALL LIVING NIGHTMARE MADE OUT OF ENERGIES. To put it in detail, the properties of his blowpipe (a magical weapon) only state that it launches projectiles at high speed at the slightest exhalation. As for the poison, it's stated that he makes his own from what he can find in the warp. Yep, you read that correctly: Oxyotl makes poisons strong enough to kill Great Unclean Ones out of literally nothing.
Oxyotl's legend actually dates back to the first Chaos incursion. Back then he and his fellow Skinks took on interceptor roles, ambushing Daemon legions and weakening them before the main forces could take them down.
Unfortunately this became a war of attrition the Lizardmen could not win, and his forces were pushed back into the temple city of Pahuax. It wasn't much longer before the Daemons were inside the city, slaughtering Lizardmen by the truckload. The city's Slann, Lord Pocaxalan, opted to try and blow them up in a massive explosion of magical energy. Unfortunately this backfired and tore open a portal to the Warp and sent the entire city of Pahuax into it. The city aged to dust in a matter of seconds and Lord Pocaxalan was eaten by daemons.
Oxyotl soon found himself trapped in the realm of Chaos. Rather than succumb to the madness like a little bitch, Oxyotl decided that he would just keep doing what he was literally born to do: Killing Daemons and taking names. Unlike Draigo however, Oxyotl didn't rely on plot armor and bullshit psychic abilities. Nope, he just picked up his trusty blowgun and went to work. For countless years he remained there, due to the nature of the Warp it's not really clear exactly how long he was trapped, but by his own perspective he returned to Lustria about 7000 years after he had left. Exactly how he escaped is still a mystery; he never spoke of how he managed it, and the Slann were (rightly) afraid to scan his mind for fear of what they might find.
While Oxyotl was in the realm of chaos, he glimpsed into many horror that would drove a mortal mad, especially visions about the end times where the dark gods destroy the world. He eventually found a way back to the mortal world, probably a distortion fabric of reality caused by the chaos gods or whatever random event happens in the warp. He got out. We can assume that Tzeentch was pleased with the changes he caused to the realm, and decided to warp him back.
His return was took as a sign of the End Times, and well... turns out they weren't all that far off as those events kicked off not too long after he had returned. Though he still had enough time to solo a Lord of Change.
Oxyotl had a brief role in the Thanquol End Times book, killing Skaven and Chaos alike as usual. However he was last seen disappearing into the Jungles to resume his hunt. It's not really clear if he was killed after that, but he wasn't mentioned to have boarded the ships when the Slann evacuated (At least not by name. Most likely however, he survived by staging Guerilla warfare against the forces of Chaos up until either the pieces of the Chaos moon smashed Lustria to ruin or the world was swallowed up into the Warp.)
If the latter, he probably sighed "Sotek damn it, here we go again!" and went back to hunting Daemons in the warp again, this time in search of a path to Azyr (which he may well have found, considering there are still rules for a "chameleon skink stalker" in the Lizardmen section on the AoS app). Though he was dropped from the Seraphon army list (Because otherwise Draigo would be much less of a special snowflake), so who really knows.
Once again, CA turning a named hero option from the tabletop into a lord like they've done so many times before (Gor-Rok, Tiktaq'to). This time in the The Silence and the Fury DLC, the orange badass is called back from his usual guerrilla warfare at the chaos realm to find an artifact called the Heart of Darkness before his rival: Taurox The Brass Bull could use it to seal the vulnerable part of his throat.
On The Tabletop
Nope, no model. It's annoying isn't it? Failing that, get a Skink and give him a Necron sword. He got a model in the 8th edition and he has an unique magic item called "The Golden Blowpipe of P'Toohee". GW has brought him back for a limited time.