diff --git a/server/gameserver/mt/Buff.cc b/server/gameserver/mt/Buff.cc
index ac618697..4a598451 100644
--- a/server/gameserver/mt/Buff.cc
+++ b/server/gameserver/mt/Buff.cc
@@ -105,6 +105,13 @@ namespace mt
                 _tags.insert(a8::XValue(str).GetInt());
             }
         }
+        {
+            if (a8::lisp::Expr::MaybeExpr(duration_time())) {
+                _duration_time_expr = LispEnv::Instance()->CompileSkillNumberExpr(duration_time());
+            } else {
+                _duration_time = a8::XValue(duration_time()).GetDouble();
+            }
+        }
         {
             std::vector<std::string> strings;
             a8::Split(post_remove_action(), strings, '|');
@@ -331,32 +338,72 @@ namespace mt
                  skill_meta
                  );
         }
-        return 0.0f;
+        return _duration_time;
     }
 
     float Buff::GetBuffParam1(Creature* c, const mt::Skill* skill_meta) const
     {
-
+        if (_buff_param1_expr) {
+            return LispEnv::Instance()->EvalSkillNumberExpr
+                (
+                 _buff_param1_expr,
+                 c,
+                 skill_meta
+                 );
+        }
+        return _buff_param1;
     }
 
     float Buff::GetBuffParam2(Creature* c, const mt::Skill* skill_meta) const
     {
-
+        if (_buff_param2_expr) {
+            return LispEnv::Instance()->EvalSkillNumberExpr
+                (
+                 _buff_param2_expr,
+                 c,
+                 skill_meta
+                 );
+        }
+        return _buff_param2;
     }
 
     float Buff::GetBuffParam3(Creature* c, const mt::Skill* skill_meta) const
     {
-
+        if (_buff_param3_expr) {
+            return LispEnv::Instance()->EvalSkillNumberExpr
+                (
+                 _buff_param3_expr,
+                 c,
+                 skill_meta
+                 );
+        }
+        return _buff_param3;
     }
 
     float Buff::GetBuffParam4(Creature* c, const mt::Skill* skill_meta) const
     {
-
+        if (_buff_param4_expr) {
+            return LispEnv::Instance()->EvalSkillNumberExpr
+                (
+                 _buff_param4_expr,
+                 c,
+                 skill_meta
+                 );
+        }
+        return _buff_param4;
     }
 
     float Buff::GetBuffParam5(Creature* c, const mt::Skill* skill_meta) const
     {
-
+        if (_buff_param5_expr) {
+            return LispEnv::Instance()->EvalSkillNumberExpr
+                (
+                 _buff_param5_expr,
+                 c,
+                 skill_meta
+                 );
+        }
+        return _buff_param5;
     }
 
     std::string Buff::duration_time() const
diff --git a/third_party/a8 b/third_party/a8
index c4610bed..abee0bed 160000
--- a/third_party/a8
+++ b/third_party/a8
@@ -1 +1 @@
-Subproject commit c4610bed765a4b0fea47ef34dc9ecf8fbcaf3e68
+Subproject commit abee0bed17773019250dc4ed042fa8fd8763cf23