On their second full-length, Korean septet BTS get personal across 15 tracks (including solo turns for each member) that span a spectrum of R&B, pop, and hip-hop sounds. Some songs are dramatic and soaring (Jimin’s “Lie”), others measured and thoughtful (Suga’s “First Love”), but each reveals their artistic maturation. On the full-group tracks, they raise the energy level: Alongside the tropical, EDM-inspired “Blood Sweat & Tears,” there’s a blistering fourth entry in their “BTS Cypher” rap series and a roof-raising, dance-floor-quaking closer in “Interlude: Wings.”