A quick translation of "thank you for always giving us strength" by Namjoon of the Korean hip-hop boy group BTS. ARMYs, BTS' fans, now use it to thank someone or express their gratitude in a comical way.
"Thank you, Dark souls" is a popular phrase invented and most famously used by the well-known youtuber "videogamedunkey".
It's often used in bullshit situations, or otherwise unfair scenarios.