sql - SQL Server Subquery returned more than 1 value. the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression

Question

hello guys i was create a new system on database sql then i get this is error

Msg 512, Level 16, State 1, Line 1
Subquery returned more than 1 value. This is not permitted when the subquery follows 
=, !=, <, <= , >, >= or when the subquery is used as an expression.

here is a query

Declare @Weapon INT = (Select ItemID From SRO_VT_SHARD.dbo._Inventory WITH (Nolock)      Where CharID = @CharID 
AND Slot in (Select Slot From SRO_VT_SHARD.dbo._Inventory Where CharID = @CharID And Slot   Between '6' And '7'))

Declare @WeaponType3 Tinyint =
 (Select Typeid3 from SRO_VT_SHARD.dbo._RefObjCommon where ID in 
 (Select RefItemID from SRO_VT_SHARD.dbo._Items where ID64=@Weapon))

Declare @WeaponType4 Tinyint =
(Select Typeid4 from SRO_VT_SHARD.dbo._RefObjCommon where ID = 
(Select RefItemID from SRO_VT_SHARD.dbo._Items where ID64=@Weapon))

declare @RefWeapon int = (Select top 1 ID from SRO_VT_SHARD.dbo._RefObjCommon WITH (Nolock) where 
                    Service = 1 AND
                    TypeID1=3 AND --- Weapon
                    TypeID2=1 AND
                    TypeID3=@WeaponType3 AND
                    TypeID4=@WeaponType4
                    Group by SRO_VT_SHARD.dbo._RefObjCommon.ID,SRO_VT_SHARD.dbo._RefObjCommon.reqlevel1
                    having  (MAX(ReqLevel1)<=(Select CurLevel from SRO_VT_SHARD.dbo._Char where charid = @CharID))
                    Order By ReqLevel1 Desc 
               )
if (@RefWeapon is not null) And (@Weapon is not null) And (@WeaponType3 is not null)     And (@WeaponType4 is not null)
begin
               Update SRO_VT_SHARD.dbo._Items set RefItemID= @refweapon where ID64=     @Weapon
end

i need fix for this is query