diff --git a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/MarvelousServer.java b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/MarvelousServer.java
index b908f73..5cb33c0 100644
--- a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/MarvelousServer.java
+++ b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/MarvelousServer.java
@@ -3,30 +3,53 @@ package uulm.teamname.marvelous.server.netconnector;
 import org.java_websocket.WebSocket;
 import org.java_websocket.handshake.ClientHandshake;
 import org.java_websocket.server.WebSocketServer;
+import org.tinylog.Logger;
+import uulm.teamname.marvelous.gamelibrary.json.JSON;
+
+import java.net.InetSocketAddress;
 
 public class MarvelousServer extends WebSocketServer {
     @Override
     public void onOpen(WebSocket conn, ClientHandshake handshake) {
-
+        Logger.info("New client connected. Adding new User.");
+        userManager.connectUser(conn, handshake);
+        // TODO: Send messages to UserManager, which then packages that stuff and sends it further
     }
 
     @Override
     public void onClose(WebSocket conn, int code, String reason, boolean remote) {
-
+        Logger.info("Client disconnected");
+        userManager.disconnectUser(conn, remote);
+        // TODO: Send messages to UserManager, which then removes the user and such
     }
 
     @Override
     public void onMessage(WebSocket conn, String message) {
-
+        Logger.debug("Message received: {}", message);
+        userManager.messageReceived(conn, message);
+        // TODO: Send messages to UserManager, which then packages them and sends them further
     }
 
     @Override
     public void onError(WebSocket conn, Exception ex) {
-
+        // TODO: Send errors to UserManager, which then answers with even more errors
     }
 
     @Override
     public void onStart() {
+        // TODO: Get the UserManager, and tell it that this thing is active
+    }
 
+    private final UserManager userManager;
+
+    public MarvelousServer(InetSocketAddress address, JSON json) {
+        super(address);
+        this.userManager = new UserManager(json);
+    }
+
+    /** Practically No-Arg constructor for testing. <b>NEVER USE ANYWHERE ELSE!</b>
+     * @param userManager*/
+    protected MarvelousServer(UserManager userManager) { super();
+        this.userManager = userManager;
     }
 }
diff --git a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/SUID.java b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/SUID.java
new file mode 100644
index 0000000..5e2d29d
--- /dev/null
+++ b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/SUID.java
@@ -0,0 +1,43 @@
+package uulm.teamname.marvelous.server.netconnector;
+
+import java.util.Objects;
+
+/** The SUID (or Somewhat Unique ID) is the ID described by the Name and ID that the client provides on Connect */
+public class SUID {
+    private final String name;
+    private final String deviceID;
+
+    public SUID(String name, String deviceID) {
+        this.name = name;
+        this.deviceID = deviceID;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getDeviceID() {
+        return deviceID;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        SUID suid = (SUID) o;
+        return Objects.equals(name, suid.name) && Objects.equals(deviceID, suid.deviceID);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, deviceID);
+    }
+
+    @Override
+    public String toString() {
+        return "SUID{" +
+                "name='" + name + '\'' +
+                ", deviceID='" + deviceID + '\'' +
+                '}';
+    }
+}
diff --git a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java
new file mode 100644
index 0000000..11b3eef
--- /dev/null
+++ b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserManager.java
@@ -0,0 +1,155 @@
+package uulm.teamname.marvelous.server.netconnector;
+
+import org.java_websocket.handshake.ClientHandshake;
+import org.tinylog.Logger;
+import uulm.teamname.marvelous.gamelibrary.json.JSON;
+import uulm.teamname.marvelous.gamelibrary.messages.BasicMessage;
+import uulm.teamname.marvelous.gamelibrary.messages.ErrorMessage;
+import uulm.teamname.marvelous.gamelibrary.messages.client.HelloServerMessage;
+import uulm.teamname.marvelous.server.lobbymanager.Participant;
+import uulm.teamname.marvelous.server.netconnector.UserMetadata;
+
+import org.java_websocket.WebSocket;
+
+import java.util.*;
+
+public class UserManager {
+
+    /** A set of users that aren't assigned to lobbies or character selection yet, and their resource descriptors */
+    private final HashMap<WebSocket, UserMetadata> newUsers;
+
+    /** A set of users that can reconnect if they wish to do so, and their matching Participants */
+    private final HashMap<WebSocket, Participant> readyToReconnect;
+
+    /** A set of users that only have to send the
+     * {@link uulm.teamname.marvelous.gamelibrary.messages.client.PlayerReadyMessage} to be assigned
+     * to a lobby
+     */
+    private final HashMap<WebSocket, UserMetadata> readyToConnect;
+
+
+    /** A set of users that are already assigned to lobbies or character selection */
+    private final HashSet<WebSocket> inGame;
+
+    /**
+     * A map mapping {@link SUID SUIDs} to {@link Participant Participants} to assert whether (and where to) reconnect
+     * an user
+     */
+    private final HashMap<SUID, Participant> activeParticipants;
+
+    private final JSON json;
+
+    /** Constructs a new, empty UserManager */
+    public UserManager(JSON json) {
+        this.newUsers = new HashMap<>();
+        this.readyToConnect = new HashMap<>();
+        this.readyToReconnect = new HashMap<>();
+        this.inGame = new HashSet<>();
+        this.activeParticipants = new HashMap<>();
+        this.json = json;
+    }
+
+    /** Called on a new WebSocket connection. Places the WebSocket and its ResourceDescriptor in a HashMap. */
+    public void connectUser(WebSocket conn, ClientHandshake handshake) {
+        var metadata = new UserMetadata(conn, handshake.getResourceDescriptor());
+        synchronized (newUsers) {
+            newUsers.put(conn, metadata);
+        }
+    }
+
+    public void messageReceived(WebSocket conn, String message) {
+        // TODO: Implement more than only a basic handshake
+
+        var parsedMessageOptional = json.parse(message);
+        if (parsedMessageOptional.isEmpty()) {
+            Logger.debug("Invalid message '{}' received, sending error", message);
+            sendError(conn, "Message could not be parsed");
+        } else {
+            var parsedMessage = parsedMessageOptional.get();
+
+            if (parsedMessage instanceof HelloServerMessage)
+                 handshake(conn, (HelloServerMessage) parsedMessage);
+        }
+    }
+
+    void handshake(WebSocket conn, HelloServerMessage message) {
+        if (!newUsers.containsKey(conn)) {
+            Logger.debug("websocket {} sent HelloServerMessage outside of handshake", conn);
+            sendError(conn, "Invalid message, as Handshake is already completed");
+            return;
+        }
+
+        Logger.info("Performing handshake with user '{}'", message.name);
+
+        SUID clientID = new SUID(message.name, message.deviceID);
+
+        // check if client is reconnected
+        var participant = activeParticipants.get(clientID);
+        if (participant != null) {
+            synchronized (readyToReconnect) {
+                readyToReconnect.put(conn, participant);
+            }
+        } else {
+            var metadata = newUsers.get(conn);
+            metadata.username = message.name;
+
+            Logger.trace("removing handshaking user from newUsers");
+            synchronized (newUsers) {
+                newUsers.remove(conn);
+            }
+            Logger.trace("adding handshaking user to readyToConnect");
+            synchronized (readyToConnect) {
+                readyToConnect.put(conn, metadata);
+            }
+        }
+    }
+
+    /** Sends an {@link uulm.teamname.marvelous.gamelibrary.messages.ErrorMessage} to the specified user. */
+    public void sendError(WebSocket conn, String error) {
+        Logger.debug("Sending error message '{}' to WebSocket {}", error, conn);
+        var errorMessage = new ErrorMessage();
+        errorMessage.message = error;
+        conn.send(json.stringify(errorMessage).get());
+    }
+
+    public void disconnectUser(WebSocket conn, boolean closedByRemote) {
+        // TODO: notify clients and such if the connection was in fact closed by the remote. Also remove participant
+        synchronized (newUsers) {
+            newUsers.remove(conn);
+        }
+        synchronized (inGame) {
+            inGame.remove(conn);
+        }
+    }
+
+    public boolean isUserConnected(WebSocket user) {
+        return newUsers.containsKey(user) ||
+                readyToReconnect.containsKey(user) ||
+                readyToConnect.containsKey(user) ||
+                inGame.contains(user);
+    }
+
+    public int getUserCount() {
+        return newUsers.size() + readyToConnect.size() + readyToReconnect.size() + inGame.size();
+    }
+
+    public Map<WebSocket, UserMetadata> getNewUsers() {
+        return Collections.unmodifiableMap(newUsers);
+    }
+
+    public Map<WebSocket, Participant> getReadyToReconnect() {
+        return Collections.unmodifiableMap(readyToReconnect);
+    }
+
+    public Map<WebSocket, UserMetadata> getReadyToConnect() {
+        return Collections.unmodifiableMap(readyToConnect);
+    }
+
+    public Set<WebSocket> getInGame() {
+        return Collections.unmodifiableSet(inGame);
+    }
+
+    public Map<SUID, Participant> getActiveParticipants() {
+        return Collections.unmodifiableMap(activeParticipants);
+    }
+}
diff --git a/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserMetadata.java b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserMetadata.java
new file mode 100644
index 0000000..535a238
--- /dev/null
+++ b/Server/src/main/java/uulm/teamname/marvelous/server/netconnector/UserMetadata.java
@@ -0,0 +1,14 @@
+package uulm.teamname.marvelous.server.netconnector;
+
+import org.java_websocket.WebSocket;
+
+class UserMetadata {
+    public String username;
+    public final WebSocket conn;
+    public final String resourceDescriptor;
+
+    public UserMetadata(WebSocket conn, String resourceDescriptor) {
+        this.conn = conn;
+        this.resourceDescriptor = resourceDescriptor;
+    }
+}