Mamare Touno's Log Horizon, about gamers living in the fictional MMORPG Elder Tale has teamed up with Sega's free-to-play smartphone game Chain Chronicle, a card/RPG with a battle system that has been compared to Plants vs Zombies. For the promotion, until the 24th, registering gets you a SR Soujirou Seta card. Then from the 28th through March 5th, a special raid/boss fight can get you a SSR Akatsuki card.
The campaign is also running a Twitter promotion offering a chance to win copies of a Log Horizon novel and clearfile autographed by the cast. Beyond residency restrictions, to enter, you need to follow @PirikaChro and use their form to Tweet out your selected character.