Nakai, Sacred Kroxigor of the First Spawning

Nakai may never join a unit and always moves and fights as an independent character.

Both Skinks and Kroxigor are separate units and follow all the normal rules. In addition, Kroxigor may see and charge through Skink units (including Chameleon Skinks) that are not fleeing.
A Skink unit that has a unit of Kroxigors charge through them must take a leadership test. If this is failed, they may not voluntarily move that turn.

Enemy units charged by Kroxigor through a Skirmish screen may stand and shoot as normal. For the purposes of working out range and whether the unit can stand & shoot at all, measure the distance to the point from which the Kroxigor emerge (ie the front of the Skink unit).

Skinks can move over marsh, rivers, lakes, or any other water features without penalty, and will benefit from soft cover while in such terrain.

For all Leadership tests, Lizardmen units roll 3 dice and choose the lowest 2 scores

Page 81 of the Warhammer Rulebook

Kroxigors  Carnosaurs, and Stegadons have a 4+ Scaly Skin Save

A creature with this ability may try to regenerate any wound on a 1d6 roll of 4+. Only one attempt may be made on each wound to regenerate it.
Troops that are able to can regenerate damage if not too badly hurt. Work this out as follows. When attacked in close combat, shot at, or the target of spells, calculate the number of wounds suffered as normal. Once all attacks for the phase have been made, the creature may try to regenerate. Roll a D6 for each wound suffered during that phase. If a 4 or more is rolled, that wound has regenerated. You may only try to regenerate any single wound once. Any regenerated wounds are reinstated, and models removed as casualties are replaced if enough wounds are regenerated.
The results of combat, panic, etc are worked out after creatures have regenerated (the number of wounds inflicted does not include any that arc regenerated).