In this challenge, they provided us with an MKV video containing Chinese subtitles.
since its .mkv i used the MKVToolNix in linux
executing mkvinfo
mkvinfo chal.mkv
I discovered three attachments accompanying the video: font files (.ttf). One of them is named 'Fake_Font'.
I extracted the Fake_Font
mkvextract attachments chal.mkv 1:FakeFont_0.ttf
Then i extracted the subtitles to get the Chinese text
mkvextract "chal.mkv" tracks 2:subtitles.srt cat subtitles.srt
我們歡迎您接受一生中最大的挑戰，即嘗試理解這段文字的含義
then we used photoshop to apply the Fake_Font to the Chinese text but you can use any text editor that has font tools:
FLAG :
irisctf{mkvm3rg3_my_b3l0v3d}