Since the end of February, Kalve's life has been moving between Latvia and Ukraine, in the Carpathian Sich Battalion.
He said: "In the place where we are, we are quite optimistic, because we have not given up our positions one iota. In total, we have lost 11 guys in a month, including the commander. I do not say this through a red mist, but they will be avenged, we will do it with more dedication, and that's the only way we can win this war by eliminating the occupiers."
Kalve pointed out that the war taught him to look at things differently.
"Before the war, I would definitely have been more psychologically damaged. Now I try to gather the energy and strength of my fallen comrade and go about the task with double energy. We hold a farewell the day before the funerals of the fallen. I try not to get carried away by emotions. I live while I am in Ukraine, for one day at a time, I don't plan for tomorrow, nor for the day after," he said.
Kalve believes that the war in Ukraine will continue for another year or two.
"The counterattack phase will be in the next few months. I have to harvest wheat and peas, but if they can't do without me there, I'll leave," he admitted.
There are around nine Latvians in Kalve's unit at the same time - some return home, some go back to Ukraine.
He said: "My task is to prepare soldiers to such a level that they will benefit Ukraine and come home safe and sound. Of course, this cannot be predicted when artillery is working on you. Fate, luck and also professional training mean a lot."
Asked if he remembers the first time bullets sounded overhead, Kalve answered: "Yes, it was near Kyiv. It was interesting. We protected Irpin, then we were transferred to Romanovka, that's where it happened. It was the first contact with war."
He also explained: "I assume that in the winter I will be able to devote more time to the war in Ukraine and if they do not object to the conclusion of a contract for three months, then I will do it."
Kalve emphasized that Ukrainians greatly appreciate the assistance provided by Latvia.
Going to Ukraine and saying goodbye to his family, he admitted that he was well aware that it might be the last time he saw his home and loved ones.
"Every time [I am at home] I love every corner, I still look in the rear view mirror while the roof of the house is visible. In Ukraine, I live alone in a room, and when I go on a mission, I pack things so that if I don't return, it would be clear to everyone entering the room – there are my personal belongings, there are electrical accessories. You have to reckon with it. War is war. Telephone numbers have been given to the commanders, then there is also a large map of Ukraine, which all the Latvians have written on, and at the very top are the telephone numbers of wives. If one of the Latvians gets hold of this map, we have agreed that he should be the first one to call the wife's number," Kalve said.
Kalve returns to Ukraine this week.