What if Xie Yan learns and makes TAOM version of Extinction Sword Technique(there are so many translation with different name, just pick whatever)?
Daoist Heart of Mara
This Technique was introduced in the early chapters the manhua, it essentially converts the emotions of the one who practices into Dao and many Bliss Temple Disciples and Elders practice it. If this technique is combined with TAOM he won't just need others emotions to upgrade or strengthen his technique. This in a sense could work with EDF since its based on how confident and relentless he is, his fighting spirit. EDF gives the practitioner fighting spirit which can make him unruly and his own confidence and will strengthen it, this trait can connect with Doaist heart of Mara and could help Xie Yan's cultivation as he could strengthen himself. He already has technique which originates from bliss temple Heavenly Demonic Bliss Technique, since elder joy belonged to bliss temple and the technique which he cultivates and may have created should originate from bliss temple and shimo sect( the original sect the 9 Great Demonic Sects of Han Empire originates from) even though it is merely a fragment of elder Joys actual technique.
Mantra of The Inner Demons of The Six Desires
This is one of the main foundation of TAOM, Xie Yan managed to recreate the techniques but not fully even thought it is as powerful as the 6 desires techniques it lack alot of move the actual one has and when it comes the heart desire and thought desire, the one he has may not be inferior but its a different version compared to the the true inheritance of Xinmo Sect that is cultivated by Yi Daochi and Yuan Sheng(He doesn't have complete inheritance tho). I hope to see Xie Yan get the complete inheritance which can allow him to strengthen TAOM foundation and obtain more moves especially since he will combine both version which have differences, his six desires would undoubtedly be much better and maybe powerful than the true inheritance of Xinmo sect.
Technique of Elder Joy/ Bliss Ancestor
The Heavenly Demonic Bliss Technique was use by Xie Yan combined to create TAOM. This technique is just a fragment, if he can get his hands on the full technique it could easily further enhance TAOM, it may allow others who cultivate the TAOM version of this technique that Xie Yan has handed similar to the heavenly demonic bliss technique the only difference being mara version. He could have others cultivate in his stead and may have a way to give his followers blessings or power through himself which helps him develop and promote Eternal Heavens
Demons of Attachment Technique
This is the Technique used by the Grand Elder of the Moqing sect, Xie Yan avoided this technique because the more they practice the uglier they become. Xie Yan can probably avoid the draw back with the systems help similar to how the system stops evil nature taking over the mc when he practices TAOM (Daoist canon of the Heavenly Demon evil thoughts drawback and Eight Difficulties drawbacks) or find some other way maybe after the integration the technique changes and doesn't turn the MC ugly. Its a demonic technique so its well suited with TAOM, one of the 4 eyes open manifestation is known as Demon of Attachment which Xie Yan uses with the angry demon to blow up 5 miles of a forest in chapter 447. I'm basically saying it has a good connection with the 6 desires technique and could help TAOM as its considered a demonic technique.
Maiden Scripture
This Technique is the main canon of the Moqing Sect, it is practiced by the sect leaders and usually needs special body and has to be a women but Sis Yu created a version with the help of the Shimo Dark Tunnel that is first cultivated as the Secret of Joy Technique than converted to Maiden Scripture to offset the requirement of the special body (Qin Xinci and Gongsun Pianxian both cultivate this currently). Unlike the Demons of Attachment Technique that turns the user ugly the more they practice, this technique helps the person maintain their youthful appearance whilst increasing their beauty as they practice more. Pretty sure the Demon of Attachment Technique and other Moqing Sect Innate Techniques are mainly derived from this technique.
Maiden Scripture allows it practitioner to freely change between Immortal and Demonic attributes which Xie Yan practically does now with the fusion of TAOM and FOFS since their qi is too different as TAOM is demonic qi and FOFS should be considered Immortal since it comes for Secret of Joy Technique which was most likely derived from Maiden Scripture. With this concept he maybe able to convert the Maiden Scripture in to a male version and can be the bridge between FOFS and TAOM.
He can finally be like other MCs have huge power mid battle/ level up during a fight since there is a move in the Maiden Scripture allowing the user to access future self power at the cost of lifespan. This Technique can upgraded quickly with the help of traversing the multiverse and looking at counterparts which (Xie Yan already does without the help of the sect formation but he instead inherits his counterparts memories instead which is much better) since understanding human emotions is the core of the technique.
The demonic part of the technique should strengthen TAOM and create a stronger Mara Body.
It would be cool to see him master the main canon of Moqing Sect in general.....
Elder Mara that is Against the Shanhai Immortal Realm
Similar to how Ji Yuntao got taught by Polaris from Shanhai Immortal Realm, Xie Yan could get an opportunity to strengthen TAOM and increase his understanding of of Dao of Mara from Elder Mara(the situation of how learn the techniques depend on what kind of person Elder Mara is and if he is willing). The way Elder Mara strengthen his followers is something Xie Yan can learn from to promote Eternal Heavens.
I'd love to see some suggestion I could add to this or some opinions in general which can help me visualize more scenarios and see different perspectives on ideas.
