Banner of command is one of my favorite items in the game at the moment as a jungle/support main and I see a lot of people using it poorly so I just wanted to make a little guide on how to use it effectively.
Most people still buy locket as an aegis upgrade because 1) the active is more straightforward to use and 2) the stats are more universally helpful, but banner has been making its way into pro play slowly but surely and more people seem to be picking it up in solo queue.
I’ll start things off by linking the wiki page for banner for those who aren’t familiar with its stats. It also shows the exact numbers for buffing each type of minion which is nice (but basically it just makes minions have more damage and take less).
The number 1 thing is not to buy it when you’re behind as locket is almost always a better choice. The bannered minion, no matter where you put it, is killed extremely easily if a team has control over the game and the active is pretty much a waste. Only buy it if you’re even or ahead.
Towers prioritize bannered minions, but they won’t switch targets just to attack it until their current target it dead. This means that you should almost always use it on at least the second melee minion in a spawned row or a ranged minion (cannon if available). Bannered minions take reduced damage from towers, but towers and ad carries are still the best at taking down the buffed minion.
There are two ideal situations to use banner of command. The first is using it on cannon minions when you have baron buff and you’re actively sieging a turret. Banner + baron buff is absolutely insane on cannon minions as long as 1) your team is with you to help protect or 2) nobody on the enemy team is available to deal with it.
The other situation, which will be used more often because baron buff isn’t readily available in most games, is to put it in a side lane. Banner allows you to start a slowpush in a lane from your base (so you don’t have to walk all the way to the wave), which is really effective when an objective is about to be contested. For example, if dragon is about to respawn in 1:30, you want to sit at your base waiting for the next waves to spawn and banner a cannon (melee/caster both fine if not available) in top lane. This is basically allowing you to splitpush a lane without even being in the lane. You can also, say, put it mid or bottom when planning to siege top in order to stack a wave for quick and easy rotations to other lanes.
When putting it in a side lane, try to wait for whoever is in a lane (unless they’re ap maybe and you want to delay their back) to leave before you use banner so it isn’t killed the moment it gets to the enemy wave.
Note that minions killed from buffed minions grant gold which is also a good reason to put in in a side lane so that gold isn’t going to waste on the other side of the map.
It’s really good on anyone who builds aegis, can benefit from the ap and either 1) can assist with fast barons (I can’t stress enough how broken bannered baron buffed cannons are) and/or 2) heal/shield/buff minions (soraka, karma)
Nunu can do both of these so I buy it almost every game on him unless my team is getting stomped or there’s like a sivir/varus/jayce (long range ad waveclear) on the enemy team.
Basically the most important thing about using banner is to make sure that the minion you buff isn’t quickly/easily killed which is a lot harder than it sounds. The reason I felt like making this guide is because it pains me when I see other people build it and just randomly buff up a minion only to have it die the moment it reaches the wave or an enemy champion without actually doing anything. Using banner effectively is all about knowing where your opponents are, where they’re going and where they’ll want to be in the next few minutes. It’s important to realize that it’s a strategic item, not just a “let’s make my minions stronger!” tool.