The entire Team Flare Secret HQ + Yveltal + Team Flare boss sequence was the best story sequence of any pokemon game so far 
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Edit - By the way, Aegislash is the most metagame approachable poke of the new ones. An Adamant Aegislash running left overs with 31 IVs for HP, Atk, and Def + 252 HP and 252 Atk EVs can really run circles against the majority of physical sweepers with it's combination of King's Shield, Sacred Sword and Shadow Sneak.
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
