Historically, this came about because Wizards R&D would use B for black and L for land, so U became the shorthand for blue and it's been that way ever since
1x Guardian Dreadscythe: easily the boss monster of this deck
Your four mana nets you a powerful sized on curve 4/4 with vigilance to swing and block
[R] Roasting Heat: 80+ damage
Commanding Conclusion Jerren, Corrupted Bishop | Illustration by Yongjae Choi As you can see, while lifegain and recursion are among the most common ways to build around cleric commanders, there are many other abilities they can bring to the table, especially with the introduction of backgrounds
One of the most popular blue cards to emerge from Core 21 is Stormwing Entity, since it can be combined with Opt and played on turn 3 for a reduced cost thanks to its ability