How to counter Spy in medieval mode?

Solution 1:

As a Spy main, these points hold for fighting Spies in any game mode:

• Keep your back to the wall when dueling a Spy. If a Spy is confident enough to attempt to take you on 1v1 they will be looking for opportunities to stab an exposed back - don't give them that opportunity.
• Don't fall for feigns. Otherwise known as 'Matador Stabs' or 'Strafe Stabs', a Spy will sometimes feign moving right then quickly move left (or vice versa). If you attempt to track them when aiming you may get caught off guard as the next thing you know they've got angle on your back.
• Take corners wide when pursuing a Spy. Competent Spies may attempt a 'Corner Stab'. Another feigning tactic, the Spy rounds a corner then doubles back in an arc around the corner. If you're in hot pursuit, you will round the corner, likely facing the direction you expect them to be in, but the Spy has doubled back around in a wide arc and is now in a position to stab you.
  If you take corners wide, you can see this coming and be better placed to avoid it.
• Don't get distracted - Whether a Spy gets a stab or not, their next priority is usually to get out of there. Give chase for a little bit but if you don't manage to kill him, don't break off from the front-lines to hunt him down - having you run circles in the back lines looking for him is as good as killing you.
• Don't backpedal away from Spies - Circle-Strafe away from them instead. Not only do you run slower running backwards, but a Spy may have more chance to get a 'facestab' on you if you're both bumping into each other.
  This is due to a bunch of weird lag compensation calculations: the game tries to work out where you both actually are, and it may think the Spy is behind you and allow him to backstab, even though on your screen he was clearly in front of you.
• Spies can be fast - The Big Earner gives a speed boost on kill.
• Spies can be tanky - The Kunai gives Overheal on kill

Medieval Mode

The majority of the above holds true in Medieval Mode (especially point 2, dueling spies in Medieval is like 90% feign tactics). Here are some more targeted Medieval-mode specific pointers:

• Learn the Map - DeGroot Keep is (currently) the only official Medieval Mode map - it's small but has some hidden features, for example
  • Demoknights can charge up the rock to get onto the battlements
  • Snipers can light their arrows on fire using the Braziers and Torches scattered around the map.
• Fight on the points - All three points on DeGroot Keep are partially surrounded by walls so keep your back to them as much as possible when fighting Spies. You will also be helping capture/defend the points themselves.
  • In general, avoid spending time in the Battlefield area (grass/hill) as much as possible - the map is very small, and this is the biggest and most effective area for a Spy to hang around and escape from situations in.
• Watch for drop-stabs - Spies (and any other enemy for that matter) can drop off the battlements onto Points A and B, or onto the entrance of the keep when the gate is up.
  • They can also drop from behind the tree onto the path near the cliff, so watch out for this as you sneak past on your way to 'B'.
• Listen for decloaks - Dead Ringer is one of if not 'the' most common Invis-watch on Medieval due to the ability to escape a bad situation with the 3 second speed boost, and ability to weaken critical hits (15% chance to crit in melee). Given that the map is so small, there aren't really any 'safe' spaces for a Spy to decloak in full silence.
• Spychecking still exists
  • The Mad Milk (Scout)
  • Bleed-effect weapons (Tribalman's Shiv, Boston Basher etc)
  • Sharpened Volcano Fragment (Pyro) & Lit Arrows (Sniper) will cause afterburn
  • Soldier's banners (check the 'buff' rings at friendly player's feet - Spies won't get the buff
  • Bumping/Hitting everyone with melee still works, especially in cramped-quarters like the keep's courtyard and capture points.
• Call out the Spy - Get used to pressing X+2. Also listen for other teammates calling out Spies.
• Play Spy yourself - Spies can open themselves up to backstabs just as much as any other player if not moreso, as low to mid-tier Spies have a tendency to tunnel-vision towards their target. If you see this going down, you may be able to stab him before (or directly after) he gets a teammate.

These are just some suggestions from my experience, if you need more info there is also the Community Medieval mode strategy guide on the TF2 Wiki, as well as other guides and loadout ideas on Steam, Reddit, and other places as well.

Solution 2:

Believe it or not, killing spies is not the main focus of the Medieval game mode. Capturing the points is. That is also part of the answer: Let spies come to you instead of trying to hunt for the spies.

• Charge to a point. A spy either needs to risk their lives to kill you on the point, or back off and find a better target. In either case a win for you.
• Use your teammates as an asset. Sometimes calling out spy will alert your teammates that a spy is near, allowing you to team up on the poor thing.
• Preswing common hiding spots. Also keep moving and turning, so that you have a better chance seeing a spy uncloak

If you cannot get around fighting a spy, don't walk at a spy. Make sure to back away from one, and swing at it if it comes after you.

If you need a class to counter a spy, you probably should choose a demoknight. They are relatively fast, have more hitpoints than a spy and have a decent reach. If you find yourself boxed in into spawn by spies and other baddies, remember that since you are near spawn, you can take a swing, and heal up inside. Repeat until the enemy dies, while you are still full health and use that momentum to reach an objective.