1. Why
2. How it actually works, and why it has to be the server
3. Scope: the map does not have to show the whole world
4. Death marks
5. Installing
6. Settings
7. Multiplayer
8. Licence

Everyone is on everyone's map, and the server is the one that decides. When somebody dies, their grave shows up on your map too.

The name is Old Norse merki: a mark, a sign, a banner. That is what it puts on the map: where everyone is, and where somebody fell.

Why

Valheim already has position sharing. It is a checkbox on the map, and every player answers it for themselves.

The problem is not that people hide. It is that hiding is indistinguishable from everything else. Someone who unticks that box does not vanish with an announcement - they just are not on the map, which looks exactly like being out of range, or dead, or logged off, or standing somewhere nobody has explored yet. On a server where the whole point is playing together, the one piece of information that tells you whether to go and look for somebody is a setting each person can silently turn off, and nobody else can see the state of.

Merki moves that decision to the server. Not by asking nicely - by taking the answer out of the client's hands, at the place the game stores it.

How it actually works, and why it has to be the server

Worth writing down, because it decides the shape of the whole mod.

A client reports in to the server every two seconds with its position and a flag saying whether it is sharing that position. The position is sent every time regardless of the flag - the server needs it for other reasons and does not care what the checkbox says. The server stores both, and then builds the list it broadcasts to everybody, copying each player's position into that list only if their flag says yes.

So the hiding happens on the server, using a fact the client supplied. Merki overwrites that fact the moment it arrives. The client is never consulted again, and there is nothing to work around: unticking the box still sets a bool, that bool still travels, and the server still throws it away.

This is also why a client-side version of this mod is not a weaker version. It could not force anybody onto the map, because the list a client receives carries no map position for a player who is hidden. The one thing a client does get is the world around it: the game streams everything in the few zones near you, other players included, so somebody close enough to see is on your connection either way. Past that, the player list is the only thing carrying a position, and the server writes it.

Merki leaves each player's own answer to the checkbox alone. The server's rule is applied on top of it and never saved over it, so a server that turns the rule off, or drops the mod, hands everyone back the choice they had made.

Scope: the map does not have to show the whole world

Because the server is deciding, it can decide per person. Two settings, off by default, which combine:

• Range - only players within so many metres appear on your map.
• SameBiome - only players in the same biome as you.

With both off, the server broadcasts its own untouched player list and Merki is only doing the forcing. With either on, the list is built once per recipient, which is the honest cost of the feature: the same list has to say different things to different people, so it cannot be one broadcast any more.

The reason to do this on the server rather than letting each client hide what is too far away: a rule the server states and does not enforce is exactly the thing this mod exists to stop being. If every position is on the wire, anybody running their own build sees the whole server and the scope is decoration.

Two limits worth knowing before picking a number. Positions are reported every two seconds and the list goes out every two seconds, so the edge lags by a few seconds of travel: a few steps on foot, tens of metres on a mount or a ship. And a Range smaller than the area the game streams around you hides nearby players from the map, not from your connection.

Death marks

The game already pins your own death on your own map. Merki puts it on the other players' maps as well, with the name of whoever died under the gravestone, and clears it after half an hour at most. You are never sent your own; the game's pin is already there.

That half is reported by the client that died, because a server never runs player death code. It is why this mod asks for everybody to have it rather than just the host: a player without Merki is still forced onto the map, but their deaths go unannounced, which is a hole in a feature rather than an absence of one, and invisible from the other side.

The report goes to the server, not to everybody, and the server passes it on under the same rule as the map. A player whose position is private sends no mark, and with Range or SameBiome set, only the players who would see them on the map get their grave.

Only a player's latest death is shown. Dying again moves their gravestone instead of adding a second one, because two graves for the same person make a map you have to read twice to learn one thing. If the new spot is outside what you would be shown, the old gravestone is simply taken off your map rather than left pointing at a body that is no longer there. That tells you they died again, but not where.

The name is the pin's own label, so it shows where every pin name in the game shows: on the large map once you are zoomed in far enough. The minimap never draws pin names, so it does not draw these either.

The server remembers each mark until it expires, so somebody who logs in after the death, or reconnects, still gets it. That is the case the feature is for: the friend who joins ten minutes later to help is the one who most needs to know where to go. They get the time that is left, not a fresh half hour, because the clock starts at the death and runs on the server. Whether they are in scope is measured once, from where they first stand in the world, since before that the server does not know where they are. For a brand-new character that means where the valkyrie sets them down, not the spot hundreds of metres out where the ride starts. A mark that expired while they were away is never sent.

A death is reported over the dying player's own connection to the server, and the server takes the name from that connection's character rather than from the message. So nobody can report a death for somebody else, and a gravestone only ever comes from the server.

None of it is saved. Marks live in the server's memory, so restarting the server forgets them all, which costs at most half an hour of gravestones.

Installing

Needs BepInEx. Nothing else. Through a mod manager it is one install. By hand, put Merki.dll in BepInEx/plugins/Merki/.

Then start the game once and quit. That first run writes the config file. It does not exist before the mod has loaded, which is the usual reason people think it is broken.

Settings

The file is BepInEx/config/ezomic.valheim.merki.cfg. Every setting has a comment above it, so the file explains itself.

Note that changing a default in a new version does nothing on a machine that has already run the mod. BepInEx writes every entry on first run and the saved value wins.

Multiplayer

Everyone needs it. With Core installed, the server refuses a client that does not have it, at the same build. Without Core nothing checks.

The server needs it most of all. A client with Merki on a server without it changes nothing: it waits for the server to state the rule, and a server without Merki never does.

If Core is installed, this mod registers with its version gate and the host's settings apply to everyone connected to it, and your own values come back the moment you disconnect. The one exception is Verbose, which stays yours. That matters more here than in most of these mods: a visibility rule each player sets for themselves is precisely what Merki replaces.

Without Core the mod still runs, and it degrades unevenly rather than politely. The forced visibility holds, because the server decides it out of data a client cannot withhold. The death marks do not, because anybody who joins without Merki never sends one.

Licence

MIT. See LICENSE.

Coming next

Written, not released yet. This is what the next version of Merki will carry as 0.1.0, and it can still change.