diff --git a/controllers/peer.go b/controllers/peer.go
index 2a3402d..aa81ccf 100644
--- a/controllers/peer.go
+++ b/controllers/peer.go
@@ -138,6 +138,7 @@ func (o *PeerController) Valid() {
 		o.ServeJSON()
 		return
 	} else if l.Data != nil && l.ToPeer().Verify && (l.ToPeer().Relation == peer.MASTER || l.ToPeer().Relation == peer.PENDING_MASTER) {
+		masterPeerID := l.ToPeer().PeerID
 		data := req.UpdateOne(map[string]interface{}{
 			"verify":   false,
 			"relation": peer.MASTER,
@@ -152,6 +153,12 @@ func (o *PeerController) Valid() {
 				Payload:  b,
 			})
 		}
+		// This node is now a NANO of the confirmed master: stamp its libp2p PeerID on self.
+		if self, serr := oclib.GetMySelf(); serr == nil && self != nil {
+			oclib.NewRequestAdmin(oclib.LibDataEnum(oclib.PEER), nil).UpdateOne(map[string]interface{}{
+				"master_id": masterPeerID,
+			}, self.GetID())
+		}
 		o.Data["json"] = data
 		o.ServeJSON()
 		return
@@ -280,6 +287,7 @@ func (o *PeerController) changeRelation(id string, dest *peer.Peer, user string,
 		if dest.Verify && relation == peer.PENDING_NANO {
 			relation = peer.NANO
 		}
+		wasMaster := dest.Relation == peer.MASTER
 		data := request.UpdateOne(map[string]interface{}{
 			"relation": relation,
 		}, dest.GetID())
@@ -293,6 +301,14 @@ func (o *PeerController) changeRelation(id string, dest *peer.Peer, user string,
 				Payload:  b,
 			})
 		}
+		// The peer was our master and is no longer — clear the MasterID on self.
+		if wasMaster {
+			if self, serr := oclib.GetMySelf(); serr == nil && self != nil {
+				oclib.NewRequestAdmin(oclib.LibDataEnum(oclib.PEER), nil).UpdateOne(map[string]interface{}{
+					"master_id": "",
+				}, self.GetID())
+			}
+		}
 		if rRelation == peer.BLACKLIST {
 			request.UpdateOne(map[string]interface{}{
 				"relation": rRelation,
diff --git a/go.mod b/go.mod
index a0921da..4a48816 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module oc-peer
 go 1.25.0
 
 require (
-	cloud.o-forge.io/core/oc-lib v0.0.0-20260429095623-9bb3d897b305
+	cloud.o-forge.io/core/oc-lib v0.0.0-20260527135023-cef23b5f307b
 	github.com/beego/beego/v2 v2.3.8
 	github.com/smartystreets/goconvey v1.7.2
 )
diff --git a/go.sum b/go.sum
index 0065c8e..ae3f1d6 100644
--- a/go.sum
+++ b/go.sum
@@ -58,6 +58,8 @@ cloud.o-forge.io/core/oc-lib v0.0.0-20260429050913-47d487ea8011 h1:owV5pQ+mS5xDC
 cloud.o-forge.io/core/oc-lib v0.0.0-20260429050913-47d487ea8011/go.mod h1:JynnOb3eMr9VZW1mHq+Vsl3tzx6gPhPsGKpQD/dtEBc=
 cloud.o-forge.io/core/oc-lib v0.0.0-20260429095623-9bb3d897b305 h1:1A6enYMMjK+2nFd187doD8LOMbnHxl+8EZRf6gqs8Yw=
 cloud.o-forge.io/core/oc-lib v0.0.0-20260429095623-9bb3d897b305/go.mod h1:JynnOb3eMr9VZW1mHq+Vsl3tzx6gPhPsGKpQD/dtEBc=
+cloud.o-forge.io/core/oc-lib v0.0.0-20260527135023-cef23b5f307b h1:TWhmHeurbBmdyevREh4+mHWOBehO2AK587RCIjCfvOc=
+cloud.o-forge.io/core/oc-lib v0.0.0-20260527135023-cef23b5f307b/go.mod h1:JynnOb3eMr9VZW1mHq+Vsl3tzx6gPhPsGKpQD/dtEBc=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/Knetic/govaluate v3.0.0+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=