Taverna is a Bagon, later Salamence, from the regions north of Orre and Angela. He is a wild Pokémon that migrated from his homeland in the edges of the Rienna Sovereignty to Emisre and later to Isla Triángulo, where he would become the apex predator.
“Taverna” is the name the Pokémon gives himself.
Like all dragons, Taverna is basically a scaly cat: he likes to sleep, roams about with apparently nothing to do, and demands to be the center of attention. As the chiefest predator in Isla Triángulo, he is quick and loud to strike down direct threats, such as other flying Pokémon flying high in his territory, but is content to ignore even those Pokémon otherwise.
For details of Taverna's early life before he acquired that name, check Taverna/Backstory.
Taverna arrived to Isla Triángulo at some point between 3670 and 3680 PE while looking for a place he could make his territory. He fought off the various leading Pokémon in the area and established himself as the apex predator of the entire island, even though just like Rayquaza after him he barely did much more than take week-long naps and hunt around once a week.
End spoilers.
Fate would that that sometime near 3720 he would happen to meet Ibrina Madis and he would become one of her companions when she joined forces with underground agent "S" in their pursuit of Pokefutures agents. He took part in a large number of fights during the campaign against Pokefutures from 3728 to 3732, against all of Pokefutures agents, law enforcement agents and random Trainers ( “The Guild of Rienna” N/A? ).
After the events of Generation Ⅲ (
3733 PE
(~0 after Gen1)
), Rayquaza migrated away from Sky Pillar (Hoenn) to Isla Triángulo as his resting spot. The legendary wyrm fell into what should have been a 8 years long slumber, with only a few days of preparation during which Taverna actually met it once, when Rayquaza was basking in the sunlight and Taverna had the great idea of try and pick a fight with him (
A Good Year to Rawr
). The result of the fight was not televised.
Taverna joined the defense of Isla Triángulo when the Emisre government approached with the intention of capturing or killing Rayquaza in
3734 PE
(~1 after Gen1)
and when the wyrm took to low orbit to fire upon the city of Mirtadenal, he took Ibrina Madis as a rider to try and get to the dragon before it could fire, joining several other Trainers attempting such a feat; but they were unable to do so in time.
After the events of Generation Ⅴ, Taverna is basically retired living as an apex predator in the island and accompanying Ibrina in some of her journeys to the continental regions, and in at least one such occasion he actually participates in some fun and games with the Trainer and some of her colleagues as well as the Trainer's romantic interest ( Cuasi Legendario ).
Barring crippling injury or return to the wild, Taverna should be able to live up to around 3850 PE, about a full century past the events of G1.
As a wild Salamence with little in the way of instruction in Trainer styles of combat, Taverna's personal style can be considered to be quite simple: greet a threat with an Hyper Beam or a similar move, and if the threat won't back down after that, go down to it and make it back down by way of claws. He is largely a frontal attacker and can handle himself well in aerial chases and in general in spaces that have a lot of vertical focus.
Living in the wild Taverna developed his own unique move, Steam Blast (see below); unfortunately for him, Lugia separately developed the move before he did.
(Note 1): These moves debuted in A Good Year to Rawr.