Les dix cartes Brave-Kin Duo, Lifecreed Duo, Skyskipper Duo, Lightshell Duo, Daggerfang Duo, Glidedive Duo, Kindlespark Duo, Roughshod Duo, Bakersbane Duo et Treeguard Duo, de l'édition Bloomburrow, forment un cycle appelé "Duo", chaque créature combinant deux des quatre types de créature associés à la couleur dans l'édition. De plus leurs textes d'ambiance se font écho.
Ce cycle est inspiré d'un autre cycle paru dans l'édition Shadowmoor (voir cette anecdote).

Source (The Glue - "[...] We ended up using an idea we'd talked about in Lorwyn design, what we call duos. The idea of a duo is that it represents two creatures working together. This allows us to put two creature types on the card, making it attractive to drafters drafting either creature type. The duos are two cycles, both at common, and both monocolor, making use of each creature type twice. This also helps with boosting the as-fan of each creature type.")