Joshua acts as Cain McDonnell's personal butler and unwavering companion. Their connection stretches back to childhood, forged when Cain was a lonely rich boy and Joshua his only friend. A marble Cain gave Joshua in their youth became a potent symbol of their bond.

Joshua pledges unwavering loyalty to Cain, consistently backing his pursuits even amid Cain's arrogance or morally dubious deeds. This devotion extends to extremes, including a readiness for physical sacrifice like considering a cliff jump. However, Cain's deliberate destruction of the childhood marble—signaling his full descent into a darker path—shatters this loyalty, provoking Joshua's pivotal decision to betray him.

Joshua engineers this betrayal not from malice but as a calculated attempt to pummel the jerkass out of him, aiming to fracture Cain's negative patterns and revive the kinder soul Joshua once knew. Their dynamic features sharp banter and a complex, often tense partnership, embodying the "Vitriolic Best Buds" trope. Joshua's every action stems from a desire to protect Cain's well-being and steer him toward redemption, even through harsh methods.