I am currently playing a Level 5 Battle Master Fighter, who is able to use a Battleaxe and the Topple Mastery (CON save), and Trip Attack (STR save) from my Battle Master maneuvers to knock enemies prone. Do you think it would be overkill for me to take the Shield Master Feat at Level 6, which would allow me to force an enemy to make a third saving throw (STR save) to avoid being knocked prone?

It seems to me that the number of saving throws that you can force an enemy to make to avoid being knocked prone, in this case could be as many as 3, would increase your odds of knocking an enemy prone? 

I am trying to figure out if I should take Shield Master at Level 6. If making an enemy make 3 saving throws is overkill, then I might want to take something else.

TIA

That’s going to depend on you and your group, and if it would get tedious. It will make your turn longer, that’s for sure. And don’t forget as you level in fighter, you’ll get more and more attacks, so more and more chances to use your topple weapon. So the real risk is, after you pile all these chances on, after you knock down something, all the other powers become useless, since they’re already down. To me, the shield is the way to go, knock them prone with your BA, then have advantage on your main attacks. 
Also keep in mind, depending on party composition prone can work against you, as all the ranged attackers in the party will have disadvantage. 

It depends on what you’re going for, if you just like knocking things over then go for it. I don’t think it’s necessary personally, especially since there’s a lot of better options and prone isn’t a necessary condition to inflict (especially if you have two ways of doing it already). Prone can also put your ranged attackers at disadvantage. If you’re building around prone, I’d say the best way to go about that would be some kind of crit fishing thing (maybe barbarian levels for brutal critical, lance and piercer if you want to extra lean into it).

Overall though, as a fighter you should probably cover your weak points more, like your mobility and other forms of control, and usefulness out of combat. Fey touched, mobile, and magic initiate are excellent feats, as well as sentinel or great weapon master. Slasher cuts movement which is nice too.

As a dislcaimer though, I’m not as familiar with 6e and I’m not sure how much those feats have changed, so take my advice with a grain of salt.

Quote from cynophobia_ >>

It depends on what you’re going for, if you just like knocking things over then go for it. I don’t think it’s necessary personally, especially since there’s a lot of better options and prone isn’t a necessary condition to inflict (especially if you have two ways of doing it already). Prone can also put your ranged attackers at disadvantage. If you’re building around prone, I’d say the best way to go about that would be some kind of crit fishing thing (maybe barbarian levels for brutal critical, lance and piercer if you want to extra lean into it).

Overall though, as a fighter you should probably cover your weak points more, like your mobility and other forms of control, and usefulness out of combat. Fey touched, mobile, and magic initiate are excellent feats, as well as sentinel or great weapon master. Slasher cuts movement which is nice too.

As a dislcaimer though, I’m not as familiar with 6e and I’m not sure how much those feats have changed, so take my advice with a grain of salt.

 I took Sentinel at Level 4 and I took two Magic Initiate feats at level 1 to gain spells and cantrips to aid me in battle but they have fallen off at Level 5, even when I can combine Battle Master Maneuver damage to them (Blade Ward 2024, Booming Blade, Green Flame Blade, True Strike, Silvery Barbs, and Protection from Evil & Good. Originally I was going to choose Eldritch Knight for my subclass, but went with Battle Master instead. It's a Curse of Strahd campaign and I am not sure what direction I want to go in. We have no Clerics in our party, and there is also a Paladin and Barbarian and I've even thought about multi-classing into Paladin, so I can gain bonus attacks with War Priest after 3 levels (My WIS is currently 15). I am also contemplating other feats like Fey Touched (for Hunter's Mark and Misty Step), Heavy Armor Master, Charger, and Gift of the Chromatic Dragon. if Shield Master would be overkill in knocking enemies prone, I will choose something else.

Paladin multiclass would be great, but since you didn’t start out with paladin levels, you’re going to be very behind in terms of spell slots. Could be worth it for a Strahd campaign though. True Strike universally sucks, and cantrips on a fighter primarily are going to be useful for out of combat, unless you’re multiclassing into bladesinger or something. But yes, to the original point, shield master is kind of overkill.

Quote from cynophobia_ >>

Paladin multiclass would be great, but since you didn’t start out with paladin levels, you’re going to be very behind in terms of spell slots. Could be worth it for a Strahd campaign though. True Strike universally sucks, and cantrips on a fighter primarily are going to be useful for out of combat, unless you’re multiclassing into bladesinger or something. But yes, to the original point, shield master is kind of overkill.

 I'd love to be able to be able to take 2 levels of Paladin, but CHA was a dump stat. I'd love to add Divine Favor and Divine Smite to my character. I actually asked our DM if I can do a slight respec so I can do so, and she said she may allow it at some point but with some sort of penalty. I have a feeling that she may use Strahd in some way that would allow me to slightly respec. The 2024 version of True Strike is good, but it fell off at Level 5. I chose it because my Fighter needed some way to deal radiant damage against some undead. I mowed through some Shadows with it in Death House, but I haven't really used it that often since then. It's only going to be situationally useful against foes who take extra damage from radiant damage.