Who said "Humor, even in darkness, is the mark of an unbroken spirit."?

This quote is attributed to Lady Sif.

Humor, even in darkness, is the mark of an unbroken spirit. - Lady Sif

"Humor, even in darkness, is the mark of an unbroken spirit."

Lady Sif Humor

"I am a warrior of Asgard, and I will not falter in the face of darkness."

"Strength is not measured by the power of one's blade, but by the resolve of one's heart."

"A true friend stands beside you, not behind you."

"We are forged in battle, but refined through compassion."

"Never underestimate the power of a good laugh."

"Laughter is the best medicine."

"A good laugh is the best medicine."

"Laughter is contagious and wonderful."