Timeline Battle lets you fight against other players in 3 vs 3 battles. You will be ranked depending on the points you earn, and can be either promoted or demoted.
It's able to be found in the Arena. Completing Timeline Battles allows you to obtain Honor Tokens, the only place these can be obtained making it the only place to reliably obtain certain Biometrics. In addition, these missions allow placement in the weekly leaderboards, which rewarding varying amounts of Crystals depending on your placement.
Unlike regular missions, Timeline Battles consume no Energy. However, you are limited in the number of times you can enter each day. You can attack other people at a max of 30 times a day, 10 times for free but requiring Crystals to pay for more oppurtunities.
Each successful fight will earn you 75 Honor Tokens, and a variable amount of points based on how many points you have compared to them. You'll also gain bonus points if you win multiple battles in a row, starting at +1 up to a max of +10. If you lose, you'll still get 50 Honor Tokens but you'll lose points.
Assists and Bonuses
You'll earn a passive stat bonuses for each hero you have of a certain class: