The will to keep living... The resolve to change fate. Let's call this power... "Determination."ENTRY NUMBER 5, True Lab
Determination is naturally possessed by humans. Should a monster acquire a high concentration of determination, its body melts, usually into an amalgamate. The only known monster who may naturally possess determination is Undyne. A being without a SOUL can gain the will to live if it acquires determination, a prime example being Flowey.
SAVE Points can be found throughout the game. These SAVE points express the protagonist's determination and thoughts in regards to recent events.
True Pacifist Route
In the True Lab, it is revealed that Alphys started experimenting with determination extracted from human SOULs in an attempt to unleash the power of the SOUL. She used blueprints to operate the DT Extraction Machine to obtain determination and began injecting it into the bodies of monsters who had fallen down. However, since their bodies cannot handle determination, the monsters injected with determination soon melted together and became Amalgamates.
Undyne, fueled by her determination, challenges the protagonist as Undyne the Undying. When defeated, she melts in a similar fashion to Amalgamates; This is also the case when she dies in her normal form.
When using a save point, it only says "Determination.", with no context in particular.
- The SAVE point description in Temmie Village refers to determination as "detemmienation."
- "Determination" might be a play on words, as the primary power it affords is the ability to reverse death, either the protagonist's or those they may have killed, hence de-termination.
- It is unknown if the Amalgamates mimicking game elements such as the protagonist's "!" dialogue box or SAVE points are actually happening and related to the Determination they have been injected with, or are simply breaks of the fourth wall intended to catch players off-guard.
- The DT Extraction Machine resembles most parts of Photoshop Flowey (Most notably the inverted mouth and the eye sockets).
- ↑ "ENTRY NUMBER 5 I've done it. Using the blueprints, I've extracted it from the human SOULs. I believe this is what gives their SOULs the strength to persist after death. The will to keep living. The resolve to change fate. Let's call this power... "Determination"." - Entry Number 5, True Lab
- ↑ "And when I tried to load my save file... It didn't work. Your DETERMINATION! Somehow, it's even greater than mine!" - Flowey
- ↑ "You see, unlike humans', monsters' bodies don't have enough... Physical matter to take those concentrations of "determination." Their bodies started to melt, and lost what physicality they had. Pretty soon, all of the test subjects had melted together into... Those." - Alphys, True Lab
- ↑ "ENTRY NUMBER 8 I've chosen a candidate. I haven't told ASGORE yet, because I want to surprise him with it... In the center of his garden, there's something special. The first golden flower, that grew before all the others. The flower from the outside world. It appeared just before the queen left. I wonder... What happens when something without a SOUL gains the will to live?" - Entry number 8, True Lab
- ↑ "ENTRY NUMBER 1 This is it... Time to do what the King has asked me to do. I will create the power to free us all. I will unleash the power of the SOUL." - Entry number 1, True Lab