Devi Chand like others of the people belonging to Arya Samaj believe in one true G-d.
Arya Samaj (Sanskrit ārya samāja आर्य समाज "Noble Society" Hindi आर्य समाज, Bengali আর্য সমাজ, Punjabi ਆਰੀਆ ਸਮਾਜ, Gujarati આર્ય સમાજ) is an Indian religious movement that promotes values and practices based on the infallibility of the Vedas. The sect was founded by Swami Dayananda, a sannyasi, on 7 April 1875. https://en.wikipedia.org/wiki/Arya_Samaj
The Vedic Schools represented the first practical application of Dayanand's vision of religious and social reform which was based on Vedic tradition. They enjoyed a mixed reception. On the one hand, students were not allowed to perform traditional idol worship of stone sculpture (murti puja in Hindi) at the Gurukul, and were instead expected to perform sandhya (a form of meditative prayer using vedic mantras with divine sound and pronunciation from the Vedas) and participate in agnihotra twice daily in morning https://en.wikipedia.org/wiki/Arya_Samaj
Brahmo Samaj. This reform organization, founded in 1828, held many views similar to those of Dayanand in matters both religious (e.g., a belief in monotheism and the eternality of the soul) and social (e.g., the need to abolish the hereditary caste or varna system and uplift the masses through education). https://en.wikipedia.org/wiki/Arya_Samaj
The Principal Core Belief of the Samaj are as follows: The belief in only One Supreme Almighty or creator known by name AUM (as mentioned in 40.17 Yajur Veda) Infallible Authority of Vedas https://en.wikipedia.org/wiki/Arya_Samaj
I give here some passage from Yajurveda in support of the topic:
CHAPTER IV:25 25. I adore God, the Creator of the Earth and Sky, the Source of all Knowledge, the Embodiment of Splendour, the Sustainer of all the beautiful planets, the Centre of love, the object of praise by the Vedas, and their Revealer. His lofty effulgent Self is divulged in the created world. He has fixed the bright sun and the moon in their conduct. He is the wisest Actor. His mercy grants us happiness. O God I worship Thee as Bestower of happiness on mankind. May all mortals enjoy life, through Thee. May Thou grant life to all human beings. https://archive.org/stream/yajurveda029 … p_djvu.txt Just tell me! Devi Chand, the translator of the above verses of Yajurveda, has taken the line that gods mentioned in Veda, are symbolic or metaphoric, and hence are manifestations of the attributes of ONE-GOD. Right? Please Regards