It tends to bite everything, and it is not a picky eater. Approaching it carelessly is dangerous.
– Pokemon Black Pokedex
Deino is the first Dark/Dragon Pokemon in the National Dex (its typing being unique to its family). It’s also the first non-pure Dragon Pokemon in the Unova dex. Its Pokedex entry and its appearance indicate that it’s blind, but its evolutions have sight.
Deino evolves at level 50, the highest for a 1st stage evolution in a 3-stage evolution chain by level. It also evolves into its final form later than any Pokemon, at level 64.
Stat-wise, it’s slow, and has more Attack than Sp Attack, even though when it’s fully evolved, it’ll have more Sp Attack than Attack. Due to Dark Pulse no longer being a TM in Gen V, Deino can only learn it through breeding with Pokemon (Arbok or Seviper) that has learned Dark Pulse in Gen IV. It’s kind of annoying, since Dark Pulse is one of the few Special Dark moves.
Deino’s family is considered Gen V’s pseudo-legendary. Though I kinda wish it’s pure Dragon type, since Dark gives it weaknesses to Bug and Fighting (which Dragon doesn’t resist).