Marvel Comics today released a pair of new teasers for its upcoming, unnamed event that seemingly has a strong supernatural focus. Both Hellstrom and the Winter Soldier are the latest heroes to join the event that, thus far, has only been advertised with the phrase “No compromise, no mercy.”

The Winter Soldier and Hellstrom join a roster that already includes Angela, Wiccan, Blade and Spectrum. Those character additions were announced separately in their own teasers, and more are sure to come before June 11, the date on which Marvel claims “all will be revealed.”

The Winter Soldier is James Buchanan Barnes, often referred to simply as “Bucky,” a former sidekick to Captain America before a near-fatal accident robbed him of his left arm. Bucky’s arm was eventually replaced with a bionic one by Russian agents, who then used him as a tool of destruction throughout the years before he opted to become a hero.

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Daimon Hellstrom is the son of a demon and a human woman named Victoria Wingate, affording him a human appearance with many of the same powers as a demon. Daimon’s sister is Satana Hellstrom, another human and demon hybrid who serves as an antihero in several stories and an antagonist in others.

More information about the mysterious event will be revealed on June 11 on Marvel’s The Pull List podcast.