Similarly to what happened to Solo Shuffle in Dragonflight, The War Within is formalizing Battleground Blitz addition to the PvP modes of WoW. This addition includes new seasonal rewards exclusive to the mode.
From datamining, we can see that there will be three rewards given every Season: one temporary title, one permanent title, and one toy.
The temporary title and the toy are rewarded by Strategist: The War Within Season 1, which requires winning 25 Battleground Blitz matches while at Elite rank during the season. The permanent title is rewarded by Forged Marshall: The War Within Season 1/Forged Warlord: The War Within Season 1. The Strategist title likely lasts until the start of the next season, similar to .
It is unsure if this title will change every season like Gladiator titles or if it will be the same title given every Season like /.
Besides seasonal achievements, there are a couple more typical achievements added to the mode as can be seen below.