The answer is: Joab

2 Sam 23:8-12 - Also Adino the Eznite in the KJV. There were another thirty mighty men listed, but these three were above the thirty

While Joab indeed held a prominent role as David's military commander, it’s true that he's never listed among the elite three mighty men, who were known for their extraordinary valor and skill in battle. The group, described in 2 Samuel 23:8-12, primarily consists of Adino the Eznite, who single-handedly killed 800 men in one encounter, and two others—Eleazar and Shammah—who also performed astounding feats of bravery.

Isn't it fascinating to think about the camaraderie and loyalty shared among David’s warriors? They must have forged incredible bonds amidst the chaos of battle. This brotherhood mirrors other tight-knit groups in the Bible, such as Jonathan and David's deep friendship, which shocked and shaped the narratives of their time.

And speaking of powerful pairs, the champion David faces before he even ascends to kingship is Goliath, a giant renowned for his strength. David’s defeat of Goliath starts to shift the country’s focus from Saul's reign to David’s glory. Joab, ironically, also becomes instrumental in shaping David's rule and power, especially when it comes to enforcing David’s decisions and capitalizing on strategic victories. So while he wasn’t in David’s inner circle of the mighty men, he certainly left an indelible mark on David's kingdom through his loyalty and prowess in warfare.

Also, those who followed David included a wide mix of backgrounds and experiences, showcasing how anyone can step up in loyalty to a genuine leader.