Edited you can use all of his health, to deal 6 damage. Thank you Death by chocolate!
I have done this scenario....what... a dozen times, and I always have a blast with it. So many different ways of ending the game, the way each mechanic crosses in a different way. It's also a lot easier to beat compare to the other standalones, plus you can earn your exp back and more easy. I,therefore, and surprised that no one has made a review on this card. I'll take a Crack at it.
You have to be a pretty convincing Liar, or have a ton of evidence to prove your innocence, to have him on your side. Once he's on your side tho, he will be a blessing, dealing damage as good as taking it. You will probably be taking a weakness, which it's not the worst, but pretty annoying, like most weakness are.
Please note that while I'll list some stuff, he rocks the banner of a neutral card.(as do all standalone assets) so anybody can take him. There are some ouchy stuff to address before I dig deeper.
1 Ally slot/1 per deck- this is pretty obvious. He takes an ally slot. You can't necessarily build for him, along side other ally assets. Typically when I build a deck(like others) you have allys in your (or splash) class that you want (or need) to take. As you have to complete MatEH to obtain Sgt. Monroe, you'll find it easier with some exp in your deck. Some exp that you've spent on a ally already. You can buy charisma with exp you earn in the Excelsior, but really....paying 3 exp to use one card is hard because....... drumroll you can ONLY have one copy. You better get lucky with your opening hand/mulligan, or have decent card draw/card tutor to get it out.(that's what calling in favors is for)
5 resources. YIKES expensive. I think for what he does, the price is abit fair. But that's not pocket change. Especially if you use the above method with charisma, two ally assets is alot of money, so you better have ways of filling your coffers, because he won't help you there. Every class has ways of obtaining money,(some better than others of course.)
Those are alll the biggest downsizes I can see, but let's see what he is good at.
Tanking- 3/3 is nothing to sneeze at. Especially since other players can put damage/horror on him as long as they are at his location.
Testless Damage- this is amazing. Once per turn, any damage/horror you deal to him he dishes back to an enemy at the location, you can deal up to 4 (actually 6) damage before he is killed. Other players can Trigger it, and the best of all. It doesn't matter HOW he is dealt damage/horror, from enemies, AoO, or treachery cards from the mythos, it doesn't matter.
The above points are fine, If you can handle the slot, drawing him, and paying for him. He will preform.
Guardian- They are usually fighting, which means engaging enemies and taking damage(and horror) he can do both of these things for you, with cards like trusted and the star , this will keep him alive longer, and emergency aid to heal damage and first aid(lvl 3) to heal horror.
Seekers- they are the best at drawing cards and searching the decks, you can draw him, put him down and not have to worry about enemies bothering you. Seekers can also help get sgt. Monroe out for other players.
Rogues- which class can pay for every card? That's right. Rogues have ways of paying for everything and Sgt Monroe is no exception. They also dip into fighting rolls so it will help them in the Frontline.
Survivors- The tanking/damaging bit is nice, but they are usually a poor class, but that's what a chance encounter is for. Fighting classes should always consider.
Mystic- Same as Survivors, they are a poor class, spending mostly on spells, and events. But they are still considered general support class, so you can for sure use it here.
That's about all the general uses I can think of, but let's talk per investigator real quick, I'll won't name everyone mind, but a few that stand out. I can really only think of guardians at the moment.
Tommy- My man can recur this bad boy all the time,but he might want more exp required friends.
Leo- he makes him cheaper, and a free action to play. Pretty good.
Mark- pretty decent, since he wants tanking for his poor sanity and Sophie. Pretty decent card draw at that.
Zoey- with her engaging everything that moves. She can afford it, and be queen of testless Damage.
Daniela - if enemies attack her, she can put damage on him and Trigger her ability for a bunch of extra damage.
That's about it. :) pretty neat asset.
ps you can commit him for nice icons