These two episodes exist to finish what Darkness 2nd started, and they do it by letting the animation team paint Yami in ways the TV series never could. The cliffhanger that left you hanging finally resolves, and Yami's shift hits because the show earned the emotional groundwork in everything that came before. By the time you reach the end, you've watched a character you thought you understood completely remake herself, and the fanservice becomes proof of that transformation rather than distraction from it.
These two extra episodes, numbered 13 and 14, continue To LOVE-Ru Darkness 2nd and came bundled with the seventh Blu-ray and DVD volume. The franchise centers on Rito Yuki, an Earth boy caught up in escalating, messy encounters with the female members of the royal family from the planet Deviluke. Expect the franchise's usual blend of comedy, romance, sci-fi and ecchi fanservice. If you've made it this far into the franchise, you know exactly what you're getting.