Just so it's up here too:
There's two projects coming out called "Kami no Kiba". One is a film staring Ryuga and set after the events of Goldstorm. It reunites him with characters from both of his previous two seasons.
The other is a TV series beginning on October 4th. This is what the above trailer is for. It's a prequel starring Jinga from before he was consumed by a Horror and became a dark knight, or judging by the contents of the trailer, possibly depicting it happening. Given what happened in Goldstorm it would be difficult for Jinga to be in anything set after it. I haven't seen anything suggesting whether there is any link between the two projects besides the name.