This is for Akimoto and those who are curious about this whole vampire and mate thing XD

Basically, all vampires have a mate, be it male or female. However, there is always a stronger vampire and a weaker vampire. In this case, Hyukjae is the stronger vampire and Donghae is the weaker vampire. Seeing as Donghae is already traumatised from the past experience with Siwon (a stronger vampire), Donghae is even weaker. Which means he is more prone to attacks and could die as well. When Hyukjae was saving Donghae, it was revealed that Donghae might die if Siwon were to atack Donghae again. This is due to the fact that as a weaker vampire, Donghae is emotionally and physically weaer and add on to the news that he had heard about Hyukjae being his mate yet didnt tell him, it caused Donghae to be even more emotionally weaker. That was why Hyukjae and Sungmin were worried for Donghae's life. The only way to prevent this is for Donghae to mate with Hyukjae. This is so that they can in a way 'share power'. The mind links between mates are strong so in case Donghae is attacked or in need of helkp, Hyukjae can come to his rescue and vice-versa.

All vampires have power, it's just whether they choose to use it or not. We know that Yoona has the power of mind manipulation already. As for Hyukjae, Donghae and Sungmin, their powers may or may not be revealed later -winks-  

Hope this clarified any questions you have? Now, I'm going to contine with the next chapter so til then, see ya~~