The main goal of this paper is to clarify what transmedia is, and to find out the three major strategies and several important techniques of transmedia. Transmedia is the trendiest tendency in industrial and academic field of media which faces such a huge paradigm shifting. Transmedia highly allows to expand characters who have not been protagonists, and to change narratives which are not spoken in original texts. Transmedia itself is very creative and prospective, so it is now changing the whole paradigms and customs of industrial and academic media field. It also gives permissions to change the formats of media into the other formats such as novels into films or films into games, etc. In this paper, I choose two video texts that are Gotham of Fox and Todd Philips’ Joker in order to reveal effects of transmedia strategies and techniques. These two texts show how insignificant characters can escalate their roles as much as protagonists. And Philips’ Joker, in particular, shows the very transmedia efficacy which is related with audiovisual effects that have never happened text books.