Blood Oaths can be obtained by managing a fortress or by trading with a castle. Blood Pledges can be obtained by managing a castle.
In this sentence posted on the information for CT1 section says you can get blood oaths by managing a fortress or trading with castle, so far can only obtain 1 every 6 hours for managing a fortress and by trading only get knight epulets even if I wait till the trading becomes lvl6.
Also the Blood Pledges can be seen after we defended our castle on the basement of the castle at the WH manager but can not be taken out of the NPC since it gives no option only shows the item.
Maybe this is a bug but if is not any GM can tell how to get the Blood Pledge from the WH manager in the castle since it has no option to receive it.
PS- Already petitioned this and after endless hours of waiting all I got was automatic responses.