Spatial deixis serves as an important intersection between grammatical structure and the physical setting of speech. Demonstratives are a prominent means for the expression of spatial deixis; they are found in all languages yet illustrate considerable cross-linguistic diversity in their grammatical, semantic, and pragmatic properties. So called ‘multi-opposition’ demonstrative systems may encode numerous deictic distinctions, including uncommon directional meanings such that they locate a referent through the specification of a direction projected from the deictic origo. Although deictic systems featuring such uncommon features have been noted in the literature, there is a distinct lack of in-depth investigations into the actual semantics and usage of such systems and therefore a lack of understanding about their functioning. This thesis documents and analyzes a particularly rich and spatially detailed demonstrative paradigm from both synchronic and diachronic perspectives. Kalaallisut (ISO 639-3 kal) is an Unangan-Yupik-Inuit language spoken in Greenland and by the Greenlandic diaspora in Denmark. In this study, I investigate the Kalaallisut demonstrative system with a focus on describing its exophoric, spatial semantics as well as its diachronic trajectory, evolving out of Proto-Yupik-Inuit and continuing to undergo significant change today. Kalaallisut has a large and complex demonstrative paradigm which exhibits numerous uncommon directional distinctions, which are anchored to the local, geophysical environment and include topographic, vertical, and cardinal features. Furthermore, rapid change is currently in evidence within the Kalaallisut system, reflecting broader linguistic, socio-cultural, and environmental shift underway in Greenland and across the Arctic more broadly. Thus, this thesis additionally serves as a case study examining ongoing language change within a complex conceptual and grammatical paradigm. Fieldwork for this study was conducted in Greenland (Nuuk and Sisimiut) and in Denmark (Copenhagen), utilizing a combination of structured elicitation methods, interviews, and text elicitation. This study investigates the ways in which a complex deictic system evolves over time, including which parts are stable and which are more susceptible to change, as well as considering which linguistic and extra-linguistic factors may play a role in variation and change. Core spatial categories including directional and distance distinctions are found to exhibit significant diachronic stability in this system indicating a fundamental role of space. Other aspects of the paradigm have been affected by internal language change, adaptation to different environments, and more recently socio-cultural change and language contact.