I really can't wait the next episodes so i decided to read its manga. Like in the anime, i still feel the chills in every intense situation portrayed in the manga.. I dont know why i am addicted in this anime , it has a good plot as well as its sound effects. No doubt it is the highest rated anime for in that season.
I will give you spoilers about the titans :D Reiner is the Colossal Titan Ymir is another titan Bertholdt as Armored titan
and for the next anime episodes, the intelligent titan thay attacked the 57th expedition outside the walls is Annie. ( Episode 18 )
all of them came from the 104th squad in which Eren and Mikasa belong..
Upon reading the manga, it is still ongoing and i think, at this moment, there would be 25% chance of having a season 2 for this anime Just stay tune and i'll update you more when I get some sources about the season 2 .